Physiology

Insulin isn't the enemy: what it actually does during training

The hormone dieters fear is actually essential for muscle growth

In popular diet culture, insulin often gets framed as the main villain of fat loss — supposedly the thing that 'forces' the body to store fat, so you should avoid triggering it at all costs. The real physiology is more nuanced: insulin is a hormone that helps cells absorb glucose and amino acids from the blood, and without it, normal muscle growth and recovery after training simply can't happen.

After a strength workout, muscle cells' insulin sensitivity temporarily increases — part of a mechanism that helps deliver nutrients more efficiently to the muscles you just worked, rather than wherever. The actual problem with insulin isn't its presence, but a chronically elevated level driven by a calorie surplus and a sedentary lifestyle — that's what's linked to fat storage and declining insulin sensitivity over time, not the routine spikes that follow a normal meal.

Bottom line: someone who trains and eats an adequate amount of calories doesn't need to fear carbs or the insulin spike that comes with them — it's part of the normal recovery process, not sabotage against your physique.