A new study found that immune cells called helper T cells stay locked in a pro-inflammatory state for a long time after obesity ends, even when body weight fully normalizes. Researchers fed mice a high-fat diet, then switched them back to normal food. Despite losing the extra fat, the mice's T cells remained inflamed for weeks. Only after extended weight maintenance did immune markers begin to normalize. Scientists estimate this 'obesity memory' could take five to ten years to fully reverse in humans. The findings suggest that short-term weight loss may not quickly reduce risks of type 2 diabetes or certain cancers linked to chronic inflammation. Sustained, long-term weight management appears necessary to truly reset the immune system after a period of obesity.
