New study reveals the reasons for failure of maintaining that hard earned weight loss. When you lose weight, you will consume more calories than necessary to maintain the lower weight through an increased appetite. The study showed that for every kg of weight they lost, patients consumed an extra 100 calories a day by virtue of an out-of-proportion increase in appetite.

A validated mathematical method was used to calculate energy intake changes during a 52-week placebo-controlled trial in 153 patients treated with canagliflozin, a sodium glucose co-transporter inhibitor that increases urinary glucose excretion, thereby resulting in weight loss without patients being directly aware of the energy deficit. The relationship between the body weight time course and the calculated energy intake changes was analyzed using principles from engineering control theory.

Previous studies show that metabolism slows when patients lose weight; however, these results suggest that proportional increases in appetite is likely to play an even more important role in weight plateaus and weight regain. At study end, the patients who had received placebo had lost less than 1 kg and those who had received canagliflozin had lost about 4 kg. The weight loss with canagliflozin was less than predicted, due to the patients’ increased appetite. On average, patients who received canagliflozin ate about 100 kcal/day more per kg of weight lost — an amount more than threefold larger than the corresponding energy-expenditure adaptations. “Our results provide the first quantification of the energy-intake feedback-control system in free-living humans,” the researchers write. They add that in the absence of “ongoing efforts to restrain food intake following weight loss, feedback control of energy intake will result in eating above baseline levels with an accompanying acceleration of weight regain.”

The findings suggest that an increased appetite is an even stronger driver of weight regain than slowed metabolism. “The message to clinicians is to not only push physical activity as a way to counter weight regain but also use medications that impact appetite.” In summary, the researchers conclude that the few individuals who successfully maintain weight loss over the long term do so by heroic and vigilant efforts to maintain behavior changes in the face of increased appetite along with persistent suppression of energy expenditure in an omnipresent obesogenic environment. Permanently subverting or countering this feedback control system poses a major challenge for the development of effective obesity therapies.

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