Burn: The Misunderstood Science of Metabolism
By Herman Pontzer
We burn 2,000 calories a day. And if we exercise and cut carbs, we'll lose more weight. Right?
the Hadza, who every day move around for ~4 hours and 15,000 steps, use the same amount of energy as couch-potato North Americans.
Exercise doesn't increase our metabolism. Instead, we burn calories within a very narrow range: nearly 3,000 calories per day, no matter our activity level.
Our extremely effective "metabolic compensation" shifts calories around so we break even at the end of the day no matter how much we move.
Basically, you can't lose weight through exercise. Reducing caloric intake is the only way. HOWEVER, the manifold health benefits of exercise still make it the single most healthful activity we can do.
The best diet is the one we can stick to.
It may be that the most spectacular athletic feats are the result not just of great training, but of an astonishingly efficient digestive system.
Faster metabolism = more fat reserves needed (humans have more fat than apes).
Metabolism is not optimized for ‘looking good’ or even being healthy, it is shaped by natural selection to optimize for reproduction
The slower a species burns energy, the longer it tends to live. Exercise makes you live longer by consuming energy that would otherwise go to other things.
Difference between animals: mouses channel most energy in reproducing, sparrows can channel more into maintenance and repair
We match the energy we expend to the energy we eat each day (hard to maintain weight loss)
Calorie restriction reduces base metabolic rate of cells. They work slower
Why are we fat? Food. Too much variety + engineered food designed to be overeaten
Humans focus on survival over reproduction (kids fighting disease grow less)
If you excercise, less energy can go to inflammation
High physical activity -> lower testosterone (good thing, lower rate of cancers inn reproducttive systems)
Cooked food has more available calories
Disappointing that the whole book used the imperial system
Not many solutions
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