Up until about 1800, food harvests alternated between feast and famine to such a degree that evolution favoured the Humans whose bodies could change to make less food go further. But the Human body also failed to learn to tell the difference between voluntary starvation and involuntary starvation. Hence, when you go on a diet for any reason, your body will adjust itself along the lines of “let’s make sure we do not lose that much weight again”.
Hence, past starvation is linked to present-day obesity in the sense that the more one starves at one point (especially during childhood), the more difficult they will find it to keep their weight down later.
Especially during middle and old age. Think about it. You cannot undo approximately 19,800 years where Humans had to scrounge for food in just 200.
Dean Mcintosh