The secret to a healthy weight is insulin, not calorie math. The same calorie is burned or stored depending on the insulin it triggers. Eat less and move more gives poor odds of keeping weight off. Randomized trials show a higher-fat, lower-carbohydrate diet beats a low-fat diet.
Fewer than 12.2% of US adults are metabolically healthy, based on NHANES data from 2009 to 2016. That is about one adult in eight. It is the most useful number for seeing why advice to each person keeps failing.
Is overeating the root cause of obesity?
People wrongly assume that eating too many calories is the root cause of obesity. But a calorie of food energy has different metabolic fates. It depends on the hormones around it when it arrives. The same calorie may be burned or stored depending on insulin. And insulin depends on what the calorie was made of.
Weight depends on many factors. But the one most often left out is insulin’s role in fat storage. Address that, and the math changes. Ignore it, and the math does not work in real life, however sound it looks on paper.
Does eating less and moving more work for weight loss?
Dietitians and physicians usually tell you to eat less and move more. That advice does not give good odds for losing weight and keeping it off. This is what the outcomes show. It is not a criticism of anyone’s effort.
Evidence from multiple randomized controlled trials indicates that a higher-fat, lower-carbohydrate diet beats a low-fat diet. It wins for both weight loss and cutting cardiovascular risk.
Why is it harder to lose weight each time you diet?
Weight regained after a loss often exceeds what was lost. Each new attempt gets harder. The process has a name — relapse-induced hyperplasia of adipose tissue. People call it rubber-banding or the fat yo-yo. Repeated cycles raise the number of fat cells that can store fat, and the next diet does not reverse that.
Smoking or obesity: which carries the higher hazard ratio?
A hazard ratio compares hazard rates between conditions. In context, smoking and obesity are closer than most people expect. For several outcomes, obesity does not come out ahead. This is a useful correction for anyone who sees obesity as a cosmetic issue and smoking as a medical one.
A generational and national problem
Blue Cross Blue Shield studied millennial health. It found health index scores dropped fast after a certain age, with metabolic conditions prominent. Obesity is also the leading medical reason people fail to qualify for US military service. Among young people aged 17 to 24, 27% are too obese to serve.
Around the world, chronic non-communicable disease makes up most of the disease burden. Most of it is associated with diet. The dual burden is real. Hunger persists in some groups while excess kills in others, and both are malnutrition.
How does sitting in front of the TV affect your health?
On average, every hour of TV watched after age 25 cuts life expectancy by an estimated 21.8 minutes. (Br J Sports Med. 2012 Oct;46(13):927-30.) Inactivity is not just a lack of exercise. Long stretches of sitting have their own metabolic effects.
The epidemic framing
Reversing obesity, prediabetes and type 2 diabetes is the most important public health challenge right now. When every species in a setting gets the same disease, the setting is the exposure. That matters more than whether we call it an epidemic or a pandemic.
Frequently asked questions
Why am I finding it so hard to lose weight?
Because the usual plan ignores insulin. The same calorie may be burned or stored depending on insulin. And insulin depends on what the calorie was made of. Eat less and move more does not give good odds of losing weight and keeping it off. Each regain can add fat cells, so every new attempt starts from a harder place.
How can I trigger my body to burn fat?
Change what you eat, not just how much. Whether a calorie is burned or stored depends on the insulin it triggers. That depends on what the food is made of. Evidence from multiple randomized controlled trials indicates that a higher-fat, lower-carbohydrate diet beats a low-fat diet. It wins for both weight loss and cutting cardiovascular risk.
What is yo-yo dieting?
Yo-yo dieting is the cycle of losing weight and gaining it back, often ending heavier than before. The process has a name: relapse-induced hyperplasia of adipose tissue. It is also called rubber-banding or the fat yo-yo. Repeated cycles raise the number of fat cells that can store fat. The next diet does not reverse that, and each attempt gets harder.
Related reading
- Malnutrition in Obesity and Starvation
- Energy Balance Theory of Obesity
- Minority populations and obesity
- Why Counting Calories Fails
- Addiction model of obesity
Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP
Interventional pain physician, addiction medicine specialist and obesity medicine diplomate.
Licensed in Missouri and Illinois.
Last reviewed August 25, 2026
