Obesity is a Hormonal, not a Caloric Imbalance

The Science of Weight Loss

Isn’t losing weight all about eating fewer calories and exercising more? Ummmm, dear me, no. I know that’s what you’ve been told over and over again, but everybody knows it’s not true.

“It is time to share a striking, and not widely appreciated secret”, wrote Dr. Dariush Mozaffarian, the Dean Emeritus at the Tufts School of Medicine and Director of the Tufts Food is Medicine Institute in 2022. He is one of the most cited researchers in medicine, having trained at Stanford, Columbia and Harvard before teaching at Harvard and Tufts and serving on the President’s Council on Sports, Fitness and Nutrition. So, what is this ‘striking secret’ he refers to?

The secret is that weight gain is far more complex than Calories In, Calories Out. Dr. Mozaffarian writes that for obesity, “The commonly accepted explanation is pervasive overeating: ever-increasing energy intake as the population gains weight, year after year. However, evidence does not support this hypothesis” Science says that weight gain is not simply the result of eating ‘too much’. Therefore, just eating less is likely not a successful strategy.

Over the past 20 years of meticulous data collection, the rate of obesity in the USA has skyrocketed even as Americans exercised more and ate about the same number of calories. There are clearly some other critical factors in determining weight gain other than the number of calories.

The nasty secret that nobody likes to admit is that the standard ‘Just Eat Fewer Calories’ weight loss advice definitely does NOT work. Oh sure, for 50 years we all pretended it works, but deep down, we knew it didn’t. Every scientific study proved it. Millions of people have tried it, and most have failed disastrously. “Just eat 500 calories less per day and you’ll lose 1 pound of fat per week”, they say. But few people ever did.

For example, The US Department of Agriculture, at Nutrition.gov in 2024 stated in no uncertain terms, Weight Loss can be achieved either by eating fewer calories or by burning more calories with physical…