Why can’t I lose weight? Here’s why.


For years I have watched my loved ones struggle with this question, even go to doctors and have blood drawn to find out why. Why can’t they lose weight like everyone else? Is it thyroid? Genetics? David, you’re a doctor – how come I can’t lose weight?

Honestly, I have dedicated the better part of my career to understanding and answering this question. So, here it is.

1) First, the question is probably flawed. Most of the people you are looking at likely did not lose weight – they have more likely been like that forever. Not that many people actually lose weight – less than 5 in 100 tries. So, the assumption that lots of people are losing weight is off. They aren’t.

2) Second, a complex biological response emerges every time you try. Every time you restrict your calories and/or start new exercise – a series of events occur:


a. Hunger hormones. The hunger hormone system coordinates a response that overwhelms you. The body is wired to survive, and when new exercise starts with or without less food a hormone assault is unleashed. Ghrelin goes up, leptin goes down, and the desire to seek food overtakes everything. Importantly, this response is not present in the already lean folks that try the same thing.

b. Thermogenesis. When you eat less your body slows down it’s calorie burning. Yep. It fights you every step of the way. You cut 500 calories from your diet and your body burns LESS calories to try and offset it. Again, the already lean person’s body just hums along at the same rate so they don’t have to deal with this.

c. Gut Microbiota. Overweight people often absorb more calories from a given piece of food than not. So, when you say, “I could eat the same little food as Skinny Sally over there, and still gain weight!” You’re right.

d. Stress. Stress hormones make you hungry. The body figures something unusual is happening here and we may need to go without food for a while, so stock up now.


There you have it. 95% of folks quit their diets because of this coordinated biological response. It cannot be overcome on your own.* It’s like holding your breath under water. At some point the body’s signals for air consumption win out and you burst to the surface for a big breath. Likewise, the longer you can stand the decreased calories and new exercise, the more likely you are to burst into a McDonald’s for relief.

Don’t worry though, scientists have figured out how to get past this. Stay tuned for the next post 😊. Love you all!


* Ok, everyone knows someone who white knuckled through a diet and lost weight. If they did, they probably gained it back – and if they didn’t they are an outlier. We are talking about most people here.


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