Kevin Hall

Science to Explain Bogus Weight Loss Clichés

The 3500 Calorie RuleOn the opening morning of YWM2018, Kevin Hall offered some remarkably clear science to refute a number of bogus weight loss clichés. Number one on the list: cut 3,500 calories from your diet and you’ll lose a pound of fat. Cut back 500 calories a day and you’ll lose a pound per week.

After four years, according to this logic, you’ll just disappear.

Mayo Clinic Says So

It’s really quite simple. Get back to weight loss basics, says the Mayo Clinic. Unfortunately, like so many other weight loss clichés, it’s just not true. That’s because of a little thing called homeostasis. The body takes care of itself automatically, maintaining critical functions with no effort from you. That body temperature of 98.6º? You don’t have to do a thing. It’s constant. Breathing? No problem. Even if you hold your breath, you’ll pass out and the body will take over.

And that’s why losing weight isn’t a simple matter of cutting calories. Cut 500 calories per day and you’ll lose a bit of weight initially. But the body adapts. It amps up your hunger. It gets stingy with the calories it has and stops burning so many.

The net of this dynamic system is that simple weight loss math just doesn’t work. Change an input to the system and it adapts. Hall has developed a sophisticated mathematical model that provides more accurate estimates. But the key word is estimate. And the basic fact of any estimate is that you should know it’s going to be wrong. Hopefully only a little. But sometimes by a lot.

And some estimates are better than others.

A Few Basic Thoughts

Hall left more than 500 people attending YWM2018 with some basic and helpful thoughts based on sound science. Your body resists weight loss. So the challenge of managing obesity is not losing weight. Instead, it’s all about sustainable ways to maintain a lower, healthier weight.

For this to happen, more physical activity can help. As a bonus, you’ll get other health benefits. Rearranging the environment around you can help, too. Take away food cues and other factors that promote mindless eating.

Drugs can help. But anyone who thinks you can simply use them for weight loss and then stop is dead wrong. That thinking doesn’t work for blood pressure or cholesterol. And obesity is no different. It’s a chronic disease that requires chronic care.

For Hall’s slides, click here.

Kevin Hall, photograph courtesy of NIH / NIH Record

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July 21, 2018