Why Weight Gain Can Occur on Insulin Therapy

Author: Chantelle van der Merwe

Registered Dietitian (SA). PGDip Diabetes Management (UK). 

If you've been experiencing unwanted weight gain and struggling to find the root cause, you may be surprised to learn that your insulin levels could partially be to blame. This is because when a person takes insulin, their body begins absorbing glucose again, and any excess glucose that is not immediately used for energy is converted into fat. 

There are several factors that can influence how much weight a person may gain while on insulin therapy. These include age, sex, height, the amount of insulin used with each meal, the level of insulin resistance, genetic makeup, family history, ethnicity, and diet and exercise habits.

Additionally, a person who takes insulin for diabetes may be gaining weight if they eat more due to concerns about developing hypoglycemia, or low blood sugar. Hypoglycemia can occur if a person takes too much insulin or skips a meal, and can cause symptoms such as dizziness, confusion, and shakiness. To prevent hypoglycemia, some people may eat more food or consume more carbohydrates than they normally would, which can lead to weight gain.
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It's important to note that weight gain is not a reason to stop taking insulin therapy. Insulin is a life-saving medication for people with diabetes, and stopping or adjusting insulin therapy without medical supervision can have serious consequences. Instead, it's important to work with a healthcare provider and a registered dietitian to develop a plan that manages blood sugar levels effectively while also addressing weight concerns. This may involve adjustments to insulin doses, changes in diet and exercise habits, and other strategies to support overall health and well-being.