Given the first law of thermodynamics, consuming fewer calories than my body expends will yield weight loss.
The greater the caloric restriction, the faster and more significant the weight loss will be.
Over the past few weeks, I’ve adhered to a relatively low calorie diet (LCD) – consuming less than 1500 calories per day.
My primary reason for implementing a low calorie diet was to determine whether it may reduce my neuropathic pain.
I have relatively severe bilateral neuropathic pain in my hands – my neurologist claims that my radial and median nerves aren’t firing properly, and that this is likely nerve pain that I’m experiencing.
Because my BMI was slightly high for my height, and because weight loss typically enhances nerve function, I implemented a low calorie diet to lose weight.
After a few weeks I’ve managed to drop from 188 lbs. to 174 lbs. (keep in mind that a large amount of this weight loss was probably “water weight” in the first week).
In any regard, the fact that I’ve been on a fairly low calorie diet sparked my curiosity and got me researching evidence-based health benefits of low calorie diets.
This led me to discovering a more extreme diet referred to as the very-low calorie diet (VLCD). Inevitably, I wanted to write an article listing all benefits that I could find associated with lower calorie diets.
What is a low calorie diet (LCD)?
A low calorie diet limits calories to a “low” quantity per day.
Though caloric needs will differ among individuals based on factors such as: activity level, age, body composition, and medications – experts have defined low calorie diets as intakes between 1000 and 1600 calories per day (based upon sex).
For males, a low calorie diet falls within 1200-1600 calories per day, whereas for females, a low calorie diet falls within 1000-1200 calories per day.
- Males: 1200-1600 calories per day
- Females: 1000-1200 calories per day
Low calorie diets are efficacious for weight loss and long-term weight management.
Assuming macronutrients and micronutrient needs are met, low calorie diets are considered very safe for a majority of the population.
What’s more, low calorie diets are regarded as being equally effective for weight loss as very-low calorie diets.
What is a very-low calorie diet (VLCD)?
A very-low calorie diet limits calories to an extremely low quantity per day.
The medical definition of a very-low calorie diet is a nutritionally-complete diet that limits caloric intake below 800 calories per day.
In most cases, very-low calorie diets are ingested as liquid formulas which contain all biologically-necessary vitamins, minerals, trace elements, fatty acids, and protein for general health.
- Males & Females: <800 calories per day
Essentially, persons on very-low calorie diets mix a nutritionally-complete powder with water and drink their meals.
Very-low calorie diets are usually reserved for clinically obese individuals (with BMIs over 30) who necessitate weight loss as a result of serious or life-threatening obesity-related health complications.
The major benefit associated with very-low calorie diets is that most individuals lose 3 to 5 pounds per week.
Health Benefits of Low calorie diets (LCD) & Very low calorie diets (VLCD)
Compiled below is a comprehensive list of evidence-based health benefits associated with low calorie diets (LCD) and very-low calorie diets (VLCD).
Examples of various health benefits associated with LCDs and VLCDs include: blood pressure normalization, HDL improvement, sustained weight loss over a long-term, and reversal of Type 2 diabetes (T2D).
Understand that there may be additional benefits that haven’t been discovered and/or reported within scientific literature.
HDL cholesterol
A review conducted by Rolland and Broom (2011) discovered that a very-low calorie diet (VLCD) may favorably modulate HDL cholesterol over a long-term.
Based on the evidence evaluated by researchers, it seems as though HDL initially decreases upon initiation of a very-low calorie diet.
However, with ongoing maintenance of a low calorie diet and maintenance of a healthier bodyweight, HDL levels improve, then significantly increase.
For general reference, HDL is commonly referred to as the “good cholesterol” because it scavenges and removes unfavorable “bad cholesterol” from the bloodstream.
When HDL levels increase, risk of heart disease tends to decrease. Oppositely, when HDL levels decrease, risk of heart disease increases.
Researchers concluded that a combination of a very-low calorie diet plus weight maintenance with a low calorie diet likely favorably alters HDL cholesterol whereby risk of cardiovascular disease is reduced. (R)
Hypertension treatment
It appears as though low calorie diets (LCDs) are capable of reversing hypertension among overweight individuals.
A report by Eliahou, Laufer, Blau, Shulman (1992) discussed the fact that low calorie diets effectively reduce blood pressure, likely via altering activation within the sympathetic nervous system (e.g. decrease norepinephrine secretion) and metabolic function.
What’s more, individuals on low calorie diets may be protected against transient blood pressure increases from intake of dietary sodium.
Researchers believe that low calorie diets can successfully control refractory hypertension (high blood pressure that’s not adequately controlled by medication). (R)
Sustained weight loss
Research shows that very-low calorie diets are effective for sustaining weight loss over an extended duration.
A paper by Saris (2001) noted that very-low calorie diets remain among the most effective long-term strategies for healthy weight management.
Because body weight is influenced mostly by caloric intake (as opposed to physical activity), it makes logical sense that restricting calories within a low range would yield the best long-term health outcomes. (R)
Superior weight loss
A small-scale study conducted by Quaade and Astrup (1989) with 38 obese persons (male and female) reported superior weight loss as a result of initially using very-low calorie diets.
Specifically, study participants continued with very-low calorie diets for as long as they could tolerate.
Thereafter, each of the participants’ very-low calorie diets were supplemented with normal foods to bring up their calories to a higher level.
It was reported that using very-low calorie diets as an initial strategy to spur weight loss yielded significantly greater weight loss when used for at least 2 consecutive months than when used for a shorter-term.
Based on these results, it’s reasonable to suspect that very-low calorie diets may be the single most optimal way to initiate a diet program for obese persons. (R)
Type 2 diabetes reversal
It may be possible to reverse Type 2 diabetes with long-term adherence to low calorie diets.
A paper by Steven, Hollingsworth, Al-Mrabeh, et al. (2016) reports that following a very-low calorie diet for a minimum of 8 weeks will reverse Type 2 diabetes in a subset of patients.
Responders to a very-low calorie diet for the treatment of Type 2 diabetes generally exhibit significant: decreases in HbA1C levels, resurgence of first-phase insulin responses, drops in fasting glucose levels (below 7 mmol/L), and reductions in body weight. (R1, R2)
Note: It should be mentioned that many benefits of low calorie diets and very-low calorie diets overlap with benefits of caloric restriction.
Other possible benefits of low calorie diets
Included below are a list of health benefits associated with ongoing caloric restriction, which is essentially what you’re doing while following a low calorie or very-low calorie diet.
For this reason, I’ve listed additional potential benefits that may be attained by individuals who adhere to lower calorie diets over a long-term.
Understand that not everyone who follows a lower calorie diet is guaranteed to experience these hypothesized benefits.
Antidepressant effect
Despite the fact that very-low calorie diets have been associated with “depressive tendencies,” this association does not prove causation.
It is understood that, while initially restricting calories, many individuals experience unfavorable changes in mood such as depression and/or anxiety.
With that said, it seems as though longer-term calorie restriction may actually yield an antidepressant effect. (R)
There are many ways by which a low calorie diet may enhance mood. Zhang, Liu, Zhao, et al. (2015) mention possibilities such as modulation of: orexin, CREB phosphorylation, endorphins, ketones, neurotrophins, and serotonin.
Others speculate that antidepressant effects of caloric restriction are attained from decreased inflammation and oxidative stress.
Atherosclerosis
Evidence indicates that caloric restriction may protect against atherosclerosis in humans.
Research by Fontana, Meyer, Klein, and Holloszy (2004) assessed the influence of caloric restriction on atherosclerosis risk factors.
To conduct their research, 18 persons who had been adhering to a calorie restricted diet (for at least 6 years) to slow aging were evaluated and compared to 18 age-matched controls (persons who had been following the standard western diet).
Comparisons indicated that serum total cholesterol, low-density lipoprotein cholesterol, ratio of total cholesterol to HDL-C, triglycerides, fasting glucose, fasting insulin, C-reactive protein, PDFG-AB, and blood pressure (both systolic and diastolic) – were substantially lower among the caloric restriction group. (R)
The intima-media thickness (IMT) of carotoid arteries was also 40% reduced among those restricting calories for a long-term.
Given the findings from this study, it’s reasonable to suggest that long-term caloric restriction may protect against atherosclerosis.
Autonomic function
It is apparent that the maintenance of a low calorie diet may significantly improve autonomic function.
Researchers de Jonge, Moreira, Martin, et al. (2010) analyzed the effect of calorie restriction for 6 months on activation of the autonomic nervous system.
It was mentioned that dominance of the sympathetic nervous system (SNS) over the parasympathetic nervous system (PNS) may accelerate aging and increase risk of cardiovascular disease.
For general health, it’s better to have balance between the SNS and PNS – rather than dominance of one over the other.
Analysis by the aforementioned researchers discovered that restricting calories by 12.5% plus increasing energy expenditure by 12.5% significantly improved autonomic function – as evidenced by favorable changes in heart-rate variability (HRV). (R)
Furthermore, a study by Griffioen, Rothman, Ladenheim, et al. (2012) discovered that caloric restriction prevented autonomic dysfunction within the brainstems of mice.
Specifically, caloric restriction inhibited accumulation of alpha-synuclein in the brainstem, thereby preventing against Parkinson’s disease-like symptoms.
Based on these results, researchers hypothesized that restricting calories would favorably modulate autonomic activity within humans. (R)
Finally, a study by Stein, Soare, Meyer, et al. (2012) compared the autonomic function of humans adhering to long-term caloric restriction with humans eating a standard western diet.
It was discovered that individuals following caloric restriction exhibited significantly better autonomic nervous system function such that autonomic activity among the caloric restricted humans was similar to humans 20 years younger following standard western diets. (R)
Cognitive enhancement
Research shows that restriction of calories typically improves cognitive abilities – and overall brain function.
Because calories are restricted on low calorie diets, it’s reasonable to expect improved cognition after long-term maintenance.
A review by Gillette-Guyonnet & Vellas (2008) indicated that caloric restriction is linked to decreased neuroinflammation, reduced oxidative stress, synaptogenesis, and favorable modulation of neurotrophic/neuroprotective mechanisms (such as BDNF to promote neurogenesis).
In other words, by restricting calories, your brain should work better and be less susceptible to neurodegeneration. (R)
Immune function
Restriction of calories via a lower calorie diet may improve immune function.
It is known that being overweight and/or consuming too many calories induces systemic inflammation, which can interfere with immune function, thereby increasing the likelihood that you’ll get sick.
When you go on a low calorie diet, you’re losing adiposity (too much directly triggers an inflammatory response) and decreasing inflammation, ultimately allowing for optimal immune function.
Research by Pahlavani (2004) suggests that caloric restriction may prevent age-related immune function decline (i.e. immunosenescence) via modulation of gene expression and cytokine signaling.
What’s more, a study by Ahmed, Das, Golden, et al. (2009) indicates that a 6-month period of calorie restriction significantly bolsters the immune response of T-cells among overweight adults (both male and female). (R1, R2)
Longevity
Research in simple organisms and animals universally demonstrates that caloric restriction increases lifespan and health span.
Because calorie restriction prevents autonomic decline/dysfunction, enhances immune function, protects against cognitive decline, reduces biomarkers associated with cardiovascular disease, and decreases cancer risk – it’s fair to assume that consumption of fewer calories would result in a longer lifespan (on average) in humans – compared to non-restriction.
Moreover, there are likely a host of direct mechanisms by which chronic caloric restriction delays the aging process.
Anyone with a modicum of logical thought would assume that, if caloric restriction favorably improves a host of physiologic functions and markedly decreases risk (or delays the onset) of many diseases, then it should promote longevity.
Researchers Cava and Fontana (2013) imply that caloric restriction has potential to increase longevity in humans via numerous mechanisms, however, further research is necessary in this niche. (R1, R2)
Cancer risk
Research suggests that caloric restriction maintained over a long-term may be effective for reducing risk of various types of cancer.
Caloric restriction is known to reduce abdominal fat, estradiol, insulin, and testosterone – each of which may play a role in cancer prevention.
There are numerous additional mechanisms by which caloric restriction may facilitate an anticancer effect including via modulation of: autophagy, angiogenesis, growth factors (e.g. IGF-1), inflammatory cytokines, and the sirtuin pathway.
A meta-analysis of caloric restriction in animal models by Chen, Ling, Su, et al. (2016) reported that caloric restriction (chronic and intermittent) may prevent cancer onset and/or inhibit preexisting cancer progression, respectively. (R)
A paper by Meynet and Ricci note that caloric restriction can significantly bolster efficiency of tumor cell death following the administration of chemotherapeutic agents.
It was also noted (in the paper) that caloric restriction appears to initiate an anticancer immune response. (R)
Researchers Saleh, Simone, Palazzo, et al. (2013) also found that tumors treated with a combination of caloric restriction plus radiation regressed significantly more than when treated with standalone radiation.
Specifically, tumors treated with the combination exhibited increased apoptosis (programmed cell death) and less proliferation (growth/spreading).
Downregulation of pathways such as IGF-1R, mTOR, IRS, PIK3ca are likely mechanisms behind the therapeutic effect. (R)
Research by Longo and Fontana (2010) mentions that caloric restriction decreases likelihood of cancer by 50% in non-human primates.
These researchers suspect that caloric restriction reduces anabolic hormones, proinflammatory cytokines, oxidative stress, and growth factors to minimize odds of cancer growth. (R)
Cardiovascular disease
It is estimated that 1 of every 3 Americans has some form of cardiovascular disease (CVD).
As of current, cardiovascular disease is the leading cause of death in the United States (responsible for 1 out of every 2.8 deaths since 2004).
Among the most significant risk factors for cardiovascular disease include: obesity and old age.
Because caloric restriction is efficacious for the treatment of obesity – this alone may decrease likelihood of cardiovascular disease.
Additionally, because caloric restriction appears to slow the aging process and decrease high levels of unfavorable biomarkers associated with cardiovascular disease – it’s fair to assume that ongoing caloric restriction is cardioprotective. (R)
Examples of biomarkers associated with cardiovascular disease that improve after caloric restriction include: blood pressure, blood glucose, c-reactive protein, HDL, LDL, and serum triglycerides.
A study by Lefevre, Redman, Heilbronn, et al. (2009) revealed that calorie restriction (with or without exercise) for a 6-month term favorably modulates lipid profiles and blood pressure in healthy non-obese persons. (R)
Authors of this study concluded that, based on favorable biomarker changes, calorie restriction may decrease risk of cardiovascular disease.
Prior evidence indicates that long-term caloric restriction (3 to 15 years) significantly reduces ventricular stiffness and viscous loss of diastolic recoil – compared to healthy age-matched and sex-matched controls.
Overall, it’s relatively obvious that nutritionally-complete caloric restriction remains among the most effective methods for reducing risk of cardiovascular disease.
Inflammatory diseases
A major benefit of sustained calorie restriction is that it decreases systemic inflammation.
Systemic inflammation interferes with immune function, brain function, and is associated with the onset and progression of many serious medical conditions such as: cancer, cardiovascular disease, depression, dementia, etc.
Most experts agree that reducing systemic inflammation, especially if chronic or significant, improves general health.
Research by Meydani, Das, Pieper, et al. (2016) indicates that calorie restriction reduces circulating inflammatory biomarkers such as: total WBC count, total lymphocyte count, ICAM-1, leptin, CRP, and TNF-alpha. (R)
González, Tobia, Ebersole, and Novak (2012) suggest that caloric restriction may prove useful in the treatment of chronic inflammatory disorders such as periodontal disease. (R)
Low calorie diet (LCD) vs. Very-low calorie diet (VLCD): Which diet is better for weight management?
A meta-analysis conducted by Tsai & Waddden (2006) sought to compare the efficacy of low-calorie diets and very-low calorie diets for long-term weight management. (R)
The aforementioned researchers assessed trials with randomized designs comparing LCDs to VLCDs – with participant follow-ups for a 1-year minimum post-weight loss.
A total of 6 trials met inclusion criteria set by the researchers for the meta-analysis.
Head-to-head comparisons revealed that very-low calorie diets resulted in significantly greater weight loss over a short-term than low calorie diets.
This finding shouldn’t surprise anyone, given the fact that those adhering to VLCDs eat fewer calories than those adhering to LCDs.
That said, there were no significant differences in total weight loss over a long-term among users of LCDs and VLCDs.
Why I prefer Low Calorie Diets (LCDs) over Very-Low Calorie Diets (VLCDs)
Because LCDs and VLCDs are each effective for the management of bodyweight over a long-term, I personally favor LCDs over VLCDs for weight loss.
There are several reasons why I’d recommend LCDs over VLCDs for individuals attempting to lose weight. Keep in mind that these reasons are merely subjective.
- Binge eating: Comparison of very-low calorie diets to low calorie diets indicates that persons on very-low calorie diets (VLCDs) may significantly more binge eating behavior within 1-year after the diet. Though it’s unclear as to whether persons on the very-low calorie diets were more likely to binge eat in the first place OR whether such an extreme diet triggered some sort of compensatory binge eating behavior post-diet, it may be smarter to stick with a standard low calorie diet (due to the fact that it doesn’t correlate with binge eating).
- Constipation: A problem that’s more likely to occur among persons on a very-low calorie diet (VLCD) is constipation. Constipation occurs as a result of changes in digestive processes when consuming nothing but a liquid formula to attain calories. Though individuals on standard low calorie diets may become constipated, the constipation is generally not as severe as those on very-low calorie diets and can often be alleviated via increasing the intake of fiber.
- Diarrhea: In addition to constipation, there’s evidence that very-low calorie diets are more likely to cause diarrhea than low calorie diets. This is most likely related to the fact that very-low calorie diets have a more substantial effect upon the digestive system.
- Food variety: Many individuals will prefer diets that allow for some flexibility in terms of the foods that they consume. When on a standard low calorie diet (LCD), you’re able to plan meals with a variety of nutrient dense foods – as long as you stay below a set number of calories. Furthermore, you can even include some “junk” food as long as you’re staying below your caloric threshold and getting adequate nutrients. By comparison, because a very-low calorie diet generally involves consuming meal replacement beverages, some individuals may find this method torturous – they will want to eat “real food.”
- Gallstones: It is estimated that approximately 25% of individuals (1 in 4) will develop gallstones within several months of adhering to a very-low calorie diet (VLCD). Gallstones form as a result of reduced bile flow and increased bile concentration as a result of VLCDs. Although gallstones do not always cause pain and/or may disappear upon reinstatement of a normal calorie diet, many individuals would likely prefer to avoid this side effect. By consuming more calories on a low calorie diet (as opposed to a VLCD), gallstones can be averted.
- Lean body mass: It is known that very-low calorie diets can deplete lean body mass. This is mostly due to the fact that lean mass is biologically “expensive” – requiring enough calories to maintain. The body breaks down some of its lean mass for energy when calories are too low. To prevent extreme muscle loss on very-low calorie diets, it is necessary to consume adequate protein. That said, despite consuming high protein on a very-low calorie diet, not all lean mass will be preserved. This may lead to poorer aesthetics and atrophy of cardiac muscles, which can cause death. For improved body composition and preservation of cardiac muscles, a low calorie diet is generally favorable over a very-low calorie diet (R). Moreover, it’s fair to speculate that more significant acute weight loss on very-low calorie diets may be partly due to a significantly greater reduction of lean body mass (not something you want).
- Mood: In one study that analyzed mood of individuals after lower calorie diets, it was discovered that more individuals had depressive tendencies in the very-low calorie diet group than in the standard low-calorie diet group. While this does not prove that very-low calorie diets cause depression and/or mood disturbances, it’s not farfetched to think that extreme caloric reduction would negatively alter one’s mood.
- More calories: Most people, if given the choice, prefer consuming a greater number of calories over fewer calories. A very-low calorie diets by definition involves ingesting less than 800 calories per day (usually in the form of a “nutritionally complete” liquid formula). While it is possible to survive and be healthy on this caloric intake for a reasonable duration, many persons may report the low quantity of calories to be psychologically depressing and/or taxing. Though persons on low calorie diets may feel hungry, most will experience less hunger than persons on very-low calorie diets. Moreover, it is reasonable to presume that persons on low calorie diets will feel more satiated (and be less tempted to “cheat” on their diets) when compared to individuals on very-low calorie diets – over a long-term.
- Nutritional deficits: Individuals who utilize very-low calorie diets (VLCDs) to lose weight may end up with micronutrient / mineral (and possibly even macronutrient) deficits. These nutritional deficits could lead to lasting and/or permanent health complications, and in extreme cases, may induce unexpected sudden death. For example, consuming a VLCD with insufficient quantities of various micronutrients may yield deficits in important vitamins (e.g. vitamin B12) whereby neurological damage is incurred. Additionally, multiple reports indicate that unmonitored very-low calorie diets (VLCDs) can cause sudden death via ventricular tachycardia. Those who consume a standard low calorie diet with nutritionally-dense foods may be less at risk of nutritional deficits (and all associated complications) than persons on very-low calorie diets (VLCDs).
- Similar effect: Research supports the idea that, when utilized over a long-term, LCDs and VLCDs yield similar outcomes in terms of weight loss. In other words, you probably won’t lose significantly more weight on a very-low calorie diet compared to a low calorie diet – if you maintained each for an extended duration (e.g. 2 years). Because long-term effects of each diet are similar, it may be reasonable to recommend the low-calorie diet over the very-low calorie diet for its decreased risk of adverse effects.
- Side effects: It is understood that side effects and/adverse reactions commonly occur among individuals on restrictive diets. That said, persons on very-low calorie diets (VLCDs) may experience a greater number of side effects and/or more severe side effects when compared to persons on low calorie diets (LCDs). Cutting calories under 800 per day, as is done with very-low calorie diets, may interfere with hormone production and cause a host of neurologic problems. Furthermore, because individuals on very-low calorie diets will lose more weight over a short-term than persons on standard low calorie diets, they are at greater risk of developing a condition known as Patulous Eustachian tube – a problem which may be permanent.
- Sustainability: Though not based in evidence, it’s logical to suspect that eating a greater number of calories is more sustainable for most individuals over a long-term – compared to consuming a smaller number of calories in the form of a liquid formulation. Persons on very-low calorie diets consume under 800 calories per day, whereas persons on standard low calorie diets typically consume between 800 and 1500 calories per day (depending on height, muscle mass, and activity level). Assuming you had to pick one of these diets to sustain over a long-term, my guess is you’d probably choose the “low calorie” as opposed to the “very low calorie” diet because you’d find it easier to psychologically sustain.
- Transition: Individuals who are overweight and/or obese may have an easier time transitioning to a low calorie diet (LCD) as opposed to a very-low calorie diet (VLCD) for weight loss. Assuming someone becomes homeostatically adjusted to consuming 5000 calories per day, it may seem like torture to drop all the way down to just 800 calories on the very-low calorie diet. Though dropping down to 1500 calories per day (from 5000) may also seem difficult, it should make for a more tolerable transition.
- Uric acid levels: Although uric acid levels do not significantly differ among persons using low calorie diets and very-low calorie diets, the peak of uric acid may be greater among those using very-low calorie diets. While neither diet has been proven to aggravate uric acid disorders, one might speculate that the very-low calorie diets would be more problematic for those with a uric acid disorder (e.g. gout) (R).
Why someone might prefer a Very-Low Calorie Diet (VLCD) over a Low Calorie Diet (LCD)…
Despite the fact that low calorie diets may be favorable over very-low calorie diets for most individuals, some persons may actually prefer very-low calorie diets (VLCDs). There are some very good reasons why someone may choose to implement a very-low calorie diet (instead of a standard low calorie diet). Moreover, in some cases, a very-low calorie diet may be the medically preferred strategy for someone with clinical obesity.
- Faster weight loss: Many people are so obese that they need to lose weight as fast as possible. While a medically-supervised water-only fast may be the fastest way to lose weight, this generally requires inpatient medical care (which can be expensive). Because very-low calorie diets can be utilized in outpatient settings plus provide some energy in the form of macronutrients and aim to provide adequate micronutrients – many may prefer this method for weight loss over a water-only fast. Furthermore, weight loss with a very-low calorie diet (VLCD) will still be rapid and significantly faster over a short-term than a standard low calorie diet (LCD). Individuals who need to lose weight as fast as possible (for medical reasons) yet still want to consume some calories may need the very-low calorie diet (VLCD) instead of the low-calorie diet.
- Fewer cravings: While one might assume that eating a standard low calorie diet yields fewer food cravings than a very-low calorie diet, this may not be a universal truth. It’s reasonable suspect that some individuals will report fewer food cravings on a very-low calorie diet than a standard low calorie diet. This may be due to the fact that very-low calorie diets don’t allow for any hyperpalatable foods and/or foods that may trigger discompliance. Though largely subjective, an individual who’s tried both diets may note that he/she exhibits more food cravings on a low calorie diet as opposed to a “very low” calorie diet.
- Longevity: Another argument could be made for very-low calorie diets over low calorie diets for the sake of longevity. It is well-known that animals fed lower calorie diets live longer and exhibit improved health spans compared to those who consume standard quantities of chow. As of current, it remains unclear as to whether a very-low calorie diet is significantly better than a low calorie diet for the sake of living longer.
- Simplicity: It’s pretty simple to follow a very-low calorie diet because all you need to do is consume a specified amount of a nutritionally-formulated beverage each day and you’re done. What’s more, most individuals on very-low calorie diets are supervised by medical professionals to ensure safety. By comparison, low-calorie diets may actually be more challenging by comparison due to the fact that individuals will need to plan out their meals.
Should you try a low calorie diet (LCD) or very-low calorie diet (VLCD)?
Obviously not everyone should be on a low calorie diet or a very-low calorie diet. Prior to initiating any type of diet for weight loss, you should ALWAYS confirm its safety with a licensed medical doctor. Your doctor will verify that a low calorie or very-low calorie diet is safe in accordance with your current age, medical status, medical history, and body composition.
- Low-calorie diet: overweight or clinically obese
- Very-low calorie diet: clinically obese with health complications
If you’re overweight as evidenced by excessive body fat and/or an elevated BMI, it’s recommended to restrict calories until your weight drops to a healthy level. Those who are overweight but not clinically obese will probably do better with a low-calorie diet than a very-low calorie diet. Those who are clinically obese with obesity-related health complications may benefit more from a medically-sanctioned very-low calorie diet.
How to minimize the risks of adverse reactions on low calorie diets (LCD) and very-low calorie diets (VLCD)
If you plan to be on a low calorie or very-low calorie diet for any significant duration, it is necessary to receive regular checkups from a medical professional. By working closely with a medical professional, it’ll be easier to prevent adverse effects and/or unwanted complications associated with significant caloric restriction.
- Avoid lower calorie diets: If you already have a BMI that’s on the lower end of healthy or medically regarded as being “too low,” you should NOT restrict calories. Additionally, persons with a history of restrictive eating disorders (e.g. anorexia nervosa) should never use lower calorie diets for obvious reasons. Individuals with certain medical conditions such as Patulous Eustachian tube should be cautious when using lower calorie diets as they may cause complications.
- Bloodwork: Anyone planning on using a low calorie or very-low calorie diet should get bloodwork done before their diet – as well as while on the diet. There are a host of reasons you’d want to get bloodwork analyzed prior to, and while using, a lower calorie diet. By getting bloodwork analyzed before your diet, you’ll be able to assess important biomarkers (e.g. inflammation) – and then compare this to biomarker levels whilst on your diet – to determine whether changes are favorable. Moreover, you’ll want to get your micronutrient levels checked to ensure that you’re not deficient in anything significant while on your diet.
- Doctor communication: Regularly communicate with a medical doctor while consuming a lower calorie diet. If you experience severe side effects and/or unexpected health complications while dieting – your doctor should be informed immediately. Do not assume you’re a dieting expert based off of what you’ve read online. Each person attempting to lose weight has different needs and/or concerns that arise when losing weight – therefore, they need personalized medical care.
- Limit exercise: Persons on very-low calorie diets (VLCDs) and low-calorie diets shouldn’t be exercising much. While exercise is healthy, excessive exercise while on an extreme diet could lead to unwanted and/or severe side effects such as fainting. Basic movement such as slow walking is best during extreme dieting. Moreover, if you’re on a lower calorie diet, you won’t want to burn all of the calories that you consume through exercising – you’ll need some for energy.
- Macronutrients: Those who are using very-low calorie diets (VLCDs) should be getting an adequate amount of nutrition if they’re using a medically-endorsed liquid formula. That said, anyone on a standard low calorie diet and/or using a non-medically recommended formulation for their very-low calorie diet will need to ensure that they’re getting adequate macronutrients. Deficits in fats and/or carbs could impair hormone production and cognitive function. Moreover, adequate protein (at least 1.5-2 grams per kg of bodyweight) should help with satiety and maintenance of lean mass. (R)
- Reduce stress: Research indicates that lower calorie diets significantly increase physiologic stress. As a result, a greater amount of cortisol is secreted which might induce anxiety, depression, and/or insomnia. Anyone following a lower calorie diet should take appropriate measures to keep their stress as low as possible. (R)
- Supplements: Individuals on very-low calorie diets (VLCDs) shouldn’t need to supplement if the liquid formula they’re using is deemed nutritionally complete. That said, it’s still possible that certain individuals end up with nutritional deficiencies – despite using a nutritionally complete formula. These individuals may need to supplement with specific vitamins and/or minerals – as recommended by their doctors. Individuals on standard low calorie diets may also need to supplement to avoid micronutrient deficiencies. Moreover, some experts may recommend agents to help promote physiologic detoxification processes due to the fact that when significant weight is lost, toxins are released from fat cells into the bloodstream. Examples of supplements to consider include: calcium d-glucarate, electrolytes, glutathione, omega-3 fatty acids, and/or a multivitamin.
Medical recommendations for Very-low calorie diets (VLCDs)
Thankfully there are some general medical recommendations that’ve been outlined for using very-low calorie diets.
These recommendations were intended to help clinicians know which patients are ideal candidates for the diet, how the diet should be implemented, and the maximal duration for which the diet should be utilized.
Note: This is NOT medical advice – talk to a medical doctor if you need diet/medical advice.
Adequate protein
It’s extremely important to consume adequate protein during both very-low calorie and low calorie diets for the sake of health and body composition.
Lack of protein, especially on a very-low calorie diet, leads to cardiac muscle atrophy – which can cause death.
Work with your doctor to determine the ideal amount of protein to be consumed on a lower calorie diet for general health.
In most cases, it is recommended to consume 1-2 grams of protein per kilogram of bodyweight.
Not suitable for most persons
As of 2014, experts recommend against routinely using very-low calorie diets (VLCDs) for weight loss – even among obese persons with BMIs above 30.
In other words, a very-low calorie diet shouldn’t be used by a majority of people who need to lose some weight.
For most individuals, a standardized low calorie diet would be a better choice.
Multifactoral strategy
Experts recommend using very-low calorie diets (VLCDs) only as part of a multifaceted weight management strategy for individuals with extreme obesity who need to lose weight as fast as possible for the sake of their general health.
A multifaceted weight management strategy should also include: psychological therapy, dietary coaching, and clinical support.
This multifaceted weight management strategy is to be continued even after the very-low calorie diet is complete – along with physical exercise (post-diet).
Nutritionally complete
Though most very-low calorie diets (VLCDs) are considered “nutritionally complete,” the nutritional profile of each diet should be reviewed by a medical professional and/or dietician prior to initiation.
In some cases, individuals may attempt their own very-low calorie diets that are devoid of macronutrients and/or micronutrients – each of which could induce deleterious physiologic effects.
12-week maximum
Because very-low calorie diets (VLCDs) are likely to provoke severe adverse reactions if continued for an extended duration, experts recommend using such diets for a maximum of 12 consecutive weeks.
These diets can be followed continuously or used intermittently throughout a 12-week duration.
Following 12 weeks of implementation, it is generally recommended to use a low calorie diet (LCD) for continued weight reduction.
Reintroduction of food
When the 12-week very-low calorie diet (VLCD) is complete, patients will need to be educated regarding how they should switch from consumption of a liquid formula to whole foods.
In some cases, reintroducing food can be tricky due to the fact that the digestive system has adapted to 12-weeks of the liquid formula – making it difficult to digest whole foods.
Always talk to your medical doctor for the specific steps by which you should transition to whole foods.
Typically, patients will add soft low-fiber foods for the first 2-3 days after the very-low calorie diet followed by small amounts of blended fruits and vegetables (e.g. smoothies) in days thereafter.
Within 1 to 2 weeks after the very-low calorie diet, most individuals are able to consume whole grains, meat, and unprocessed fruits/veggies. (R)
Have you used a low calorie diet (LCD) or very-low calorie diet (VLCD)?
If you’ve ever used a low calorie diet (LCD) or very-low calorie diet (VLCD) for weight loss or general health, I’d love to hear about your experience in the comments section. Mention some specifics such as:
- Your weight before the diet.
- Total duration over which you adhered to the diet.
- Subjective level of difficulty
- Total amount of weight lost.
- Changes in general health attributable to the diet.
For the past several weeks I’ve been using a low calorie diet to shed excessive body weight.
As of last month I was slightly “overweight” based on BMI measures and I could see (in the mirror) that I had too much adipose tissue – mostly from eating junk (non-nutritious) foods (e.g. Halloween candy).
I’ve been tracking my calories with a basic food scale and the free app “MyFitnessPal” – consuming between 1300 and 1800 calories daily depending on my appetite and activity level (I eat more calories if I go for a 20-25 minute jog).
I’ve been using the app to ensure that I’m getting an adequate amount of each major macronutrient (fats, carbs, proteins) – and
I’ve been taking supplements (e.g. multivitamins) to ensure that I’m not significantly deficient in a particular micronutrient.
Though I found it difficult to follow a low-calorie diet in my first week, I’ve since had no major difficulty.
The biggest hurdle with a low calorie diet is largely psychological – you need to adapt to the feeling of hunger.
Personally, I’ve found that consuming most of my calories in the evening (as opposed to morning) works out better.
I also utilize time-restricted feeding such that I consume nearly all of my calories within a 4-6 hour window (typically between 4 PM and 10 PM).
The reason for consuming most of my calories at night is related to the fact that I’m most tempted to eat at night while watching TV, Netflix, and/or doing mindless activities until bed.
Furthermore, when I eat breakfast, I generally find that I get really hungry in the early afternoon – probably related to a glucose spike after my first meal, followed by a crash.
After just a few weeks of a low-calorie diet, my BMI is already well-within a healthy range for my height and I can see visible abdominal muscles in the mirror without flexing.
Although I’m “hungry” right now as I’m typing this article, the hunger isn’t that big of an issue – it’s something I can cope with.
I guess the most significant side effects for me have been: poorer cognitive performance (largely due to feelings of afternoon hunger), cold extremities (my body feels colder when eat less – especially in my hands), and infrequent bouts of orthostatic hypotension (probably due to “fasting” for most of the day).