Low calorie diets (generally offering fewer than 1000 cal per day) have been been extensively used for the induction of medically supervised weight loss for decades. However, as with all diets, patients regain weight as soon as the diet is discontinued.
This raises the question of how long patients can safely stay on such a diet to sustain the often dramatic amounts of weight loss.
In a paper just published in Clinical Obesity, we describe the long-term efficacy and safety of using a low-calorie diet (LCD: providing 900 kcal per day) in severely obese patients who were non-eligible for bariatric surgery.
We describe eight patients (6 men, mean age 60) with severe obesity (mean BMI 57.1) who underwent long-term LCD (33 ± 10 months).
Variables of interest included anthropometric, cardiovascular risk and nutritional parameters, thyroid, renal and liver function, changes in medications, side effects and adverse events.
On average, patients lost 44 ± 15 kg (27 ± 13% of initial weight) at 24 months.
This dramatic weight loss (comparable to what can be achieved with bariatric surgery) resulted in substantial and sustained improvements in glucose homeostasis, blood pressure and lipid profile as well as dramatic improvements in mobility and quality of life.
Overall LCD was well tolerated with minor self-limited side effect (e.g constipation, dry skin, etc.). No nutritional deficiencies were noted.
Over the follow-up period, two subjects underwent coronary revascularization and one patient underwent knee replacement surgery – all recovered without complications.
These findings suggest that in selected obese patients, long-term management with LCD may provide an alternative option for substantial and sustainable weight loss with significant improvements in metabolic and cardiovascular health.
While most people may find it difficult (if not impossible) to give up all food to sustain themselves on a liquid LCD (4 shakes a day), this unique observation at least documents that for those rare individuals for whom there may be no other alternative, this can be a relatively safe and effective strategy for sustaining a substantial weight loss in the long-term.