Why Does Insulin Make You Gain Weight?

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In a healthy person, beta cells in the pancreas secrete a hormone called insulin to help the body use blood sugar or glucose from food. Type 1 diabetics lack the ability to make insulin and Type 2 diabetics are immune to the insulin produced by the pancreas. Insulin shots may help both types of diabetics, but like any other drug, insulin has side effects, including weight gain.

Boosting Efficiency

Insulin may cause weight gain because it makes your cells more efficient. Untreated diabetics often excrete glucose in their urine. When you start insulin shots, the hormone helps your cells absorb glucose from the bloodstream, so you are theoretically retaining more calories from food.

A Side Effect of a Side Effect

Insulin often causes hypoglycemia or low blood sugar. To combat the dizziness and fatigue of hypoglycemia, diabetics on insulin have to eat frequent meals and snacks. Weight gain may simply be the result of an increase in calories.

Taking Action

Talk to your physician about the type and dose of insulin you are taking if you notice significant weight gain. Your doctor may be able to adjust your medications. A healthy diet and regular physical activity are also an integral part of weight management.