Personally, I was more surprised by the various groups of people who _don't_ have higher metabolic rates: > Children’s metabolic rates stay high until age 5, but the rate slowly begins to glide down until it plateaus around age 20. Interestingly, adult rates are stable until age 60, when they begin to decline. After age 90, humans use about 26% less energy daily, Pontzer says. > The study also found that pregnant wom…
This seems almost unbelievable to me. Almost everyone I know, with a handful of exceptions I can think of, had a dramatic change in what I can only say was metabolism at 30 declining steeply to 40. I can tell you personally my ability to lose weight when exercising daily has decreased significantly since 30. If it’s not metabolism, then what? Diet and exercise are almost identical.
I track calories/food quality, weight, plicometry, and exercise (although not all of them all the time). With precise and systematic measuments, I find easily that it's a matter of food quality, quantity, and exercise.
I'm convinced that there are several external factors that make people over 30 gain weight, more than metabolism: work, children, stable relationships and independence.
I also used to think that teenagers are fit without any effort, but if I look at them, this is generally not true. I will start believe people who claim that it's a matter of metabolism when they'll start to track food, weight and plicometry, and will go on a sports (not walking) regime. But not before.