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Treating obesity with diet restrictions and weight loss pills 

Special thanks to Maithreye and Tamara

Obesity is a gateway to many chronic diseases (cardiovascular diseases, diabetes, etc.) and is becoming a common problem today with 1 in 3 men having BMI greater than 30 which is documented as the official mark for being obese. In the figure below percent of obese men and women nearly tripled since 1975 and is still increasing.


Click here for more interactive charts and plots on world obesity


What causes obesity?

Simple answer to this seemingly difficult problem is that you are eating more calories than your body is spending. Weight loss/gain in human beings is directly related to energy imbalance between intake and expenditure. Higher energy intake than required will increase body weight and vice versa. Diet management and exercise are often advised to lose that extra weight your body has. In the recent advancements towards curing obesity several ‘magic’ pills are being discovered that claims to reduce body weight.


Pills and placebo

In a typical double blind trial that is carried out to establish drug efficacy, a pill with no therapeutic effect, a placebo (such as a sugar pill) is given to the patients instead of an actual drug so that neither patient nor doctor know if they are on intent to treat medication or not. This is a high bar to establish drug efficacy and overrule bias, incidental effects due to noise etc. and not considering a placebo arm can render the whole clinical trial inconclusive.



Weight loss protocols – Diet restriction, weight loss pill and placebo

In a recent project, we were evaluating several weight loss protocols of trials (a) diet restrictions and exercise (b) diet restrictions with weight loss pill.

(a) Trial 1, which was explicitly looking at the weight loss in obese patients by cutting exactly 500 calories per day from their regular diets shows expected results. Patients were strictly monitored to ensure compliance to the doctor’s instructions. Results showed that mean weight loss reported at the end of the trial was around 7% of their initial starting weights.


Figure 1: Mean weight loss % among patients on diet restriction protocols (namely Alternate Day Fasting (ADF) and Daily Calorie Restriction (DCR). A total of 100 (34 in ADF, 35 in DCR and 31 in the placebo arm) patients participated in the trial1.

So far so good.

(b) Another clinical trial (trial 2) was conducted to check the potency of a weight loss drug. Obese patients were grouped in placebo and non-placebo groups. Patients were to receive a diet restriction protocol AND a weight loss pill. This pill acted on nervous system and was expected to reduce the appetite of those in the treatment arm. Results showed greater weight loss in non-placebo group as compared to placebo group, again as expected.


Figure 2: Mean weight loss % among patients administered Qsymia (PHEN/TPM ER 15/92). A total of 130 (75 in the Qsymia arm and 55 in the placebo arm) patients participated in the trial2.


What is the catch?

Placebo group in the latter trial is essentially the same as the calorie restriction patients in trials 1 but lost less weight (3% as opposed to 7% weight loss). What happened here? For the patients in trial 1 weight loss was simply due to having lesser amount of food and nothing else, whereas placebo group of trial 2 were offered a pill meant to cause weight loss along with the suggestions to maintain diet restriction. Attributing the weight loss effects solely to the miraculous weight loss drug may have been a factor for not being compliant enough for an actual dietary restriction in placebo patients for trial 2!

Weight loss pill is not a magic drug after all. Weight loss comes down to restricting calorie intake and remaining compliant to it. So, if you want to lose weight better start cutting down some calories.

Click here to plan your diet protocol.



1. Trepanowski, J. F. et al. Effect of alternate-day fasting on weight loss, weight maintenance, and cardioprotection among metabolically healthy obese adults: A randomized clinical trial. JAMA Intern. Med. 177, 930–938 (2017).
2. Garvey, W. T. et al. Weight-loss therapy in type 2 diabetes: Effects of phentermine and topiramate extended release. Diabetes Care 37, 3309–3316 (2014).

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