Insulin-induced lipohypertrophy

Occurs over time, irreversible by diet alone. Mechanistic culprit - insulin, specifically chronic hyperinsulinemia. Primary culprit - dietary carbohydrates. In diabetes type 1, it occurs as a result of injecting insulin in the same spot for years, and it occurs only in that spot, resulting in local fat mass. In everybody else, it occurs systemically, but most especially around the waistline and where there is normally already more fat than elsewhere on the body.

None of this can be explained merely by "eating irregularly", nor can it be fixed by "eating regularly".

However, if we consider the Minnesota semi-starvation experiment and the subsequent follow-up that shows subjects regained weight and then some extra fat on top of that, we can reasonably conclude that deprivation eventually leads to overcompensation, and if this overcompensation is done mostly in the form of eating dietary carbohydrates, it will result in chronic hyperinsulinemia and insulin-induced lipohypertrophy. On the other hand, we can already reasonably conclude that none of that is required for chronic hyperinsulinemia - we can just eat lots of carbs now at every meal - we can just "eat regularly".