[smileysteve]

This doesn't seem to line up anecdotally;

The first outlier I see is female health and PCOS, starting in mid 20s for women.

The next outlier I see is insulin resistance and pre and diabetes based metabolism decline.

From a hormone perspective, nose, ear, chin (femalr), and head hair seem to be going under significant change.

[wredue]

Mid 20s with when your lifestyle shift just starts to catch up to you.

You go from a more active young person that eats just enough to get back to hanging with friends to binge drinking in an instant. Then you go from that to a much lazier, snackier lifestyle of 9-5.

Yeah, people on the whole do get fatter in their 30s, but that’s very easily linkable to lifestyle.

[fortran77]

This is caused from eating too much, not a decline in “metabolism”

[smileysteve]

So, the combination of the research and my anecdotes - and your response seems to be

That by our early 20s our metabolism has already slowed (sugary food, alcohol, precipitous drop in activity)

[fortran77]

No, our metabolism isn't "slow" (for 99% of people). People just start eating much more and moving much less.

[tristor]

Insulin resistance and PCOS absolutely have effects on metabolism. It’s very well studied.

[paulpauper]

how many outliers or exceptions do you need before you can throw out the theory