Adipose tissue retains an epigenetic memory of obesity after weight loss

As someone who's struggled with weight loss, and have known others to struggle with it well, I think we colloquially called this "slow metabolism".

It always did feel like it was easier to gain weight than lose it, especially fat weight and not muscle weight for me.

I was recently sent a video about fat adaptation (basically teaching your body to be better at burning fat) by a very fit friend, but I wonder how much of that is bro science and how much of it is grounded in reality. Maybe worth looking into more deeply if it can counteract or balance out this.

It is well known that if you gain muscle then lose it, it is easier to regain it than the first time (IIRC, the cells store extra nucleii?). This could be a similar effect but with fat cells.

As well as the "cell memory", the total number of fat cells you have in your body is set during adolescence, then it remains constant for the rest of your adult life. (https://www.nature.com/articles/ncpgasthep1189).

During adolescence, if you gain weight, you create new fat cells. During adulthood, the fat cells themselves just get larger. Arguably the best thing you can do is avoid obesity during childhood and adolescence at all costs.