The Hundred Faces

Putting a Number on Your Appetite

Obesity System MapIn the complex jungle of systems that influence the development and prevalence of obesity, two physiologic mechanisms stand out: metabolic rate and appetite. In new research from NIH to be presented at ObesityWeek 2016, Kevin Hall and colleagues have put a number on the role of appetite in making sure that people regain most of the weight they lose through dieting.

It turns out that every kilo of weight (about two pounds) that you lose sets up an increase in appetite that stimulates you to eat an extra hundred calories per day.

Remember that attention-grabbing story about metabolic adaptation contestants from The Biggest Loser? This effect of increased appetite is roughly three times bigger than the metabolic adaptation seen in those contestants.

These findings were a bit of a happy accident. Researchers were studying the effect of canagliflozin (Invokana) on body weight. They found that the numbers were not adding up. Canagliflozin treats diabetes by causing the body to excrete extra sugar in urine. Researchers knew exactly how many calories (360) were being lost every day because of this effect. But the weight loss was much less than they should have seen from those lost calories. And metabolic adaptation could not explain the difference.

Through careful mathematical modeling, the researchers showed that each kilo of weight loss drove people to eat 100 more calories per day. These people were not hungry because they were eating less. Their hunger increased because their bodies were leaking calories into their urine.

This study provides one more glimpse of the beautiful and powerful physiology that regulates body weight and energy balance. It’s the force of physiology at work, not the force of will.

Click here for the study and here from more from the esteemed Arya Sharma on this subject. And most important, be sure to catch Hall’s presentation of this research at the Obesity Journal Symposium during ObesityWeek 2016 in New Orleans.

The Hundred Faces, photograph © Carlos Gracia / flickr

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October 28, 2016

One Response to “Putting a Number on Your Appetite”

  1. October 29, 2016 at 11:40 am, Allen Browne said:

    Yup – physiology drives behavior. We used to be able to say physiology trumps behavior and hopefully we will be able to again after Nov 8.