Introduction:
Very low-calorie diets (VLCD) were first developed in the 1970s for cases whose body mass index (BMI) was 30 or higher end of the range, as these individuals are predisposed to a higher risk of cardiovascular diseases because of obesity. Though nutrition experts currently consider the BMI itself as quite a biased measure or index that does not take several factors into account, such as the individual body composition, ethnicity, race, age, or gender, it still remains a standard for diagnosing obesity as it is a comparatively inexpensive and quicker method in the medical industry for analyzing the patient's health status and possible weight outcomes.
What Are the Indications of VLCD?
A very low-calorie diet (VLCD) is a rapid weight-loss program that is commonly prescribed by registered professionals like dieticians or nutritionists for specific health conditions that require a low-calorie diet only to be followed particularly. It has become an undesirable trend in the last decade for even healthy individuals to restrict their calorie intake to lose weight rapidly or in a short period, without consulting a healthcare professional. The medical and nutrition literature has reportedly come up with several life-threatening cases and severe nutrient deficiencies predisposing such individuals (who are not medically supervised for VLCD) to mortality.
VLCD restrict the calorie intake of an individual on a daily basis to less than 800 calories consumption from food or even fewer as per the systemic status of the individual. A calorie level this low would be almost considered semistarvation as an analogy. This diet is hence extremely dangerous when individuals adapt it themselves without any medical supervision. This diet can be prescribed or suggested by registered health care professionals only for reasons that would specifically necessitate weight loss, such as in cases requiring surgeries to prevent postoperative weight-based complications.
Why Very Low Calorie Diet Requires Medical Supervision?
Very low-calorie diets (VLCDs) necessitate medical supervision due to the heightened risk of various medical complications.
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Electrolyte imbalance occurs when the levels of essential minerals like sodium, potassium, and calcium in the body are not in proper balance, potentially leading to muscle weakness, heart arrhythmias, and other serious issues.
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Dehydration results from an insufficient intake of fluids, which can cause symptoms ranging from mild, such as dry mouth and fatigue, to severe, including kidney failure and shock.
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Gallstones can form when rapid weight loss leads to an excess of cholesterol in the bile, causing these hard deposits to develop in the gallbladder, which can be painful and may require surgical intervention.
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Other abnormalities include nutrient deficiencies, which can affect overall health and bodily functions, and metabolic changes that can impact how the body processes and stores energy, potentially leading to long-term health issues.
Due to these risks, VLCDs must be undertaken with careful medical supervision to monitor and manage any arising complications effectively.
Can VLCD Promote Effective Weight Loss for Patients Undergoing Surgery?
The most common instance when a VLCD would be necessary, like in cases where preliminary weight loss plays an important role in post-operative outcomes is in the bariatric surgery field. A VLCD can help these individuals to have improved post-operative outcomes and also alleviate the obesity-related symptoms.
VLCD aim to mainly help obese patients achieve significant, yet short-term weight loss targets as a recommendation strategy prior to surgery or for preventing risks associated with obesity such as a comprehensive part of the weight-loss program. But the major drawback of this diet is that because the food intake itself is so limited apart from the daily calorie consumption which is restricted to around or less than 800 calories in a single day, very low-calorie diets can only be followed for certain periods even in these individuals who are indicated for it and that too must be supervised by a medical physician or professional doctor.
In most instances cited in nutrition literature, VLC diets are not recommended for patients with a BMI between 27 and 30 unless they are suffering from other lifestyle medical conditions related to their excess weight, such as diabetes (high blood glucose) or hypertension (high blood pressure). These diets are not prescribed for children or young adolescents because they are severely restrictive and cannot be an option for healthy weight loss. Even in the geriatric population groups that are considered high-risk cases for mortality, older individuals cannot often tolerate the potential side effects of VLC diets especially when they have pre-existing medical conditions.
Hence these diets can be implemented only when the physician or registered nutritionist decides whether such a diet is indeed necessary or life-saving for preventing the complications with excess weight or obesity in individuals.
According to nutrition research, even if the VLC diets are implemented for a while, the patient should eventually consult with their registered professional and switch back to consuming a low-calorie but not a restricted diet form as VLCD cannot be a long-term solution, depriving individuals both of energy and nutrition.
What Are the Advantages and Disadvantages of VLC Diet?
Advantages:
- Following a VLCD would possibly improve or alleviate the clinical symptoms associated with weight gain or obesity in patients suffering from diabetes, psoriasis (itchy, dry patches on the skin), and osteoarthritis (joint disorder).
- Improvements, including rapid weight loss, waist circumference, amount of lean mass versus body fat, nutritional quotient, or walking stride of the patient are assessed by the medical practitioner or physician post the VLCD completion and then one would be advised to switch over to a healthy and balanced diet form that would still be low on calories, but much less restrictive in terms of the food groups one can consume. VLCD can definitely result in improvements in the physical parameters of patients suffering from the conditions listed above if they are recommended by a registered healthcare professional or nutritionist.
Disadvantages:
- A VLCD can be quite strict in terms of the specific low-calorie foods to be adapted into the diet as any medium or high-calorie substitutes for the low-calorie food items indicated or dictated by the medical professional cannot be allowed.
- One may be however required to purchase only the specific meal replacement products that are a part of the prescribed practitioner-suggested VLC diet.
- It is to be noted that following a VLCD for more than four weeks and in some patients before surgery for up to 16 weeks would result in several side effects such as the frequent experience of headaches, weakness, fatigue, nausea, vomiting, constipation, fluctuations in blood sugar causing hypoglycemia, bad breath or halitosis, diarrhea, dizziness, and hair loss.
- Further patients who are suggested a VLCD would be prone to developing bone density loss within a month due to low calcium levels when the diet is followed past four weeks. Gallstones are severe complications that can develop in high-risk groups such as geriatric groups, obese individuals, or women.
Conclusion:
A very low-calorie diet is a medically supervised dietary plan that is implemented in the patient's best interest for losing rapid weight in those with obesity or particularly high BMI. In this diet, the safety concerns are quite serious even for those following the diet because they consume less than 800 calories per day, necessitating a doctor’s supervision.
