Diabetes and weight gain: what you need to know

Diabetes mellitus, often referred to as diabetes or sugar disease, includes a group of metabolic disorders in which the body is unable to properly regulate blood sugar levels. Around 422 million people are affected worldwide, and the condition significantly impacts daily life, including body weight (WHO, 2024). While being overweight is a proven risk factor for the development of diabetes, the question arises whether people with diabetes may also gain weight due to their condition. In this article, we will take a closer look at the connection between diabetes and weight gain, including the different types of diabetes mellitus and their effects on body weight.

Table of Contents

• What is diabetes mellitus?
• What types of diabetes mellitus are there?
• Is being overweight a risk factor for diabetes?
• How does diabetes affect body weight?
• How can I maintain a healthy weight with diabetes?
• Summary

What is diabetes mellitus?

The metabolic disorders classified as diabetes mellitus are characterized by chronically elevated blood sugar levels. These conditions occur when the pancreas does not produce enough insulin—a hormone responsible for regulating sugar metabolism in the body—or when body cells do not properly respond to the insulin produced. Insulin helps the body’s cells absorb and use glucose (sugar) from the blood, which is essential for energy production. When these processes are disrupted, glucose accumulates in the blood, which can lead to serious health problems, including heart disease, kidney damage, and vision loss (CDC, 2023).

What types of diabetes mellitus are there?

Below are the four main forms of diabetes mellitus:

Type 1 diabetes

This form of diabetes mellitus is often referred to as insulin-dependent diabetes and typically begins in childhood or adolescence, though it can also develop in adulthood. In type 1 diabetes, the immune system attacks and destroys the insulin-producing cells in the pancreas, leading to a complete lack of insulin. As a result, blood sugar levels remain high because glucose cannot enter the cells. This destruction is part of an autoimmune reaction, which is why type 1 diabetes is considered an autoimmune disease. Affected individuals must rely on insulin injections for the rest of their lives (CDC, 2023).

Type 2 diabetes

Type 2 diabetes is one of the most common forms of diabetes and is therefore often referred to as a widespread disease. This form of diabetes develops when the body can no longer effectively use the insulin it produces—a condition known as insulin resistance. Initially, the body can compensate for insulin resistance by producing more insulin, but over time, this ability may decline and insulin production may also decrease. The main causes and risk factors for type 2 diabetes include being overweight, physical inactivity, genetic predisposition, and sometimes older age (NIDDK, 2017).

Prediabetes

Prediabetes is a condition in which blood sugar levels are higher than normal but not high enough to be classified as type 2 diabetes. This means there is an increased risk of developing type 2 diabetes. One of the challenges with prediabetes is that it often goes undetected, as symptoms are not always obvious. However, if detected early, prediabetes is reversible, and the development of type 2 diabetes can be prevented through targeted lifestyle changes (Cleveland Clinic, 2023).

Gestational diabetes

Gestational diabetes is a form of diabetes that occurs during pregnancy and usually disappears after birth. This form develops when the body cannot produce enough insulin during pregnancy, leading to elevated blood sugar levels. Gestational diabetes poses a risk for certain complications during pregnancy and childbirth, both for the mother and the child, and should therefore be diagnosed early (NHS, 2022).

Is being overweight a risk factor for diabetes?

Obesity, particularly the accumulation of fat in the abdominal area, is a confirmed risk factor for the development of prediabetes and type 2 diabetes. A body mass index (BMI) of 30 or more—which indicates the ratio of body weight to height—is classified as obesity. Fat cells in the abdominal region release inflammatory substances that can promote insulin resistance. In insulin resistance, the body’s cells become less sensitive to the hormone insulin, so glucose from the blood can no longer be effectively absorbed by the cells. Although many people with type 2 diabetes are overweight, there are also lean individuals with this form of diabetes mellitus, highlighting the importance of other factors such as genetic predisposition (Cleveland Clinic, 2023).

Would you like to assess your own situation?

If you are overweight or concerned that you may have diabetes, the Homed-IQ Blood Sugar Test offers a convenient way to check your HbA1c level from home. The HbA1c test provides insight into your average blood sugar levels over the past three months and can be an important tool in identifying the risk or presence of diabetes at an early stage. 

How does diabetes affect body weight?

Particularly type 1 diabetes, but also poorly controlled or yet undiagnosed type 2 diabetes, as well as symptoms such as fatigue and loss of appetite, can lead to weight loss before insulin therapy is initiated. This is because the body, in the absence of insulin or with insulin resistance, cannot efficiently convert glucose into energy and therefore begins breaking down fat and muscle tissue to generate energy.

The effect of insulin on body weight:

Insulin is important for metabolism and blood sugar regulation. Insulin therapy, which is commonly used to treat type 1 diabetes and, at a certain severity, also type 2 diabetes, can lead to weight gain. This happens for several reasons:

1. Insulin’s effect on fat storage: Insulin not only helps transport glucose into cells but also supports the conversion of excess glucose into fat and inhibits the breakdown of fat. Therefore, when insulin levels are increased through insulin administration, this can lead to more fat being stored. As a result, food intake should be carefully monitored and adjusted, as unchanged or increased caloric intake in combination with the effect of insulin can lead to increased fat accumulation.
2. Reduced glucose excretion: Before starting insulin therapy—especially in poorly controlled diabetes—the body excretes excess glucose through urine. This changes when insulin is used to better control blood sugar, and the body begins to excrete less glucose. As a result, more calories remain in the body, which can potentially lead to weight gain.
3. Hypoglycemia and eating behavior: The use of insulin to control blood sugar levels in diabetes can sometimes lead to hypoglycemia (low blood sugar). Insulin lowers blood sugar levels, and when administered in too high a dose or not adjusted to food intake, it can cause dangerously low blood sugar levels. As a result of this hypoglycemia, strong cravings often occur, and large amounts of food are quickly consumed to normalize blood sugar levels. This leads to weight gain, as the body takes in more calories than it needs.
4. Changed energy balance: With the administration of insulin, the body's ability to utilize glucose improves, leading to more efficient energy production. This can result in a positive energy balance, especially if calorie intake is not reduced accordingly, which in turn may contribute to weight gain.

Sources: Sears & Peary, 2015; Mayo Clinic, 2023

How can I maintain a healthy body weight with diabetes?

Weight gain during insulin treatment can be a sign that the treatment is working, as the body starts to better utilize and store glucose. For this reason, it is important to take additional steps to keep body weight under control and maintain a healthy weight, even during insulin treatment.

What kind of diet is suitable for maintaining a healthy weight with diabetes mellitus?

With the right food choices, you can not only control your weight but also keep your blood sugar levels stable. Below are recommendations for adjusting your diet:

• Balanced macronutrients: Ensure your diet includes a healthy balance of proteins, fats, and complex carbohydrates. Proteins and fats have less impact on blood sugar levels than simple carbohydrates.
• Prefer whole foods: Choose unprocessed foods such as whole grains, fresh fruits, and vegetables, as these contain more nutrients and fiber that help stabilize blood sugar levels.
• Reduce sugar and processed foods: Avoid foods high in sugar and fat, as they can cause rapid blood sugar spikes followed by cravings.
• Frequent small meals: Eat smaller meals throughout the day to maintain even blood sugar levels and avoid sudden hunger attacks.
• Choose foods with a low glycemic index (GI): Foods with a low GI release sugar more slowly into the bloodstream, which helps keep blood sugar stable.

The following foods have a low GI:

• Non-starchy vegetables such as broccoli and cauliflower
• Whole, unprocessed grains such as barley and oats
• Legumes such as beans, lentils, chickpeas, and peas
• Nuts and seeds such as almonds, walnuts, and chia seeds
• Dairy products such as milk, yogurt, and cheese

Source: Sissons, 2024; Patel & Kayes, 2023

Why is regular exercise important in diabetes mellitus?

Regular physical activity plays a crucial role in weight management for individuals with diabetes. Exercise not only improves insulin sensitivity but also helps burn calories, thereby supporting weight normalization. Even 30 minutes of moderate walking on most days of the week can have positive effects. By lowering blood sugar levels and improving overall fitness, regular exercise can reduce the risk of diabetes-related complications. However, blood sugar levels should be monitored before and after exercise to avoid hypoglycemia, and any exercise plan should be discussed with a doctor (Zahalaka et al., 2023).

How does stress affect body weight in diabetes mellitus?

When under stress, the body produces hormones such as cortisol and adrenaline, which raise blood sugar levels to provide the body with more energy. This is problematic for people with diabetes, as their ability to regulate blood sugar is already impaired. In addition, stress often leads to unhealthy lifestyle and eating habits, such as consuming high-sugar and high-fat foods, smoking, or lack of exercise. These habits not only increase blood sugar levels but can also contribute to weight gain. Techniques such as meditation, regular physical activity, and a balanced diet can help minimize the effects of stress and support a healthy weight (Cleveland Clinic, 2024).

Summary

Diabetes mellitus affects body weight in various ways and can lead to either weight loss or weight gain. This influence is particularly noticeable during insulin treatment, which is often associated with weight gain. Careful adjustment of diet and regular physical activity are essential for managing body weight in diabetes mellitus, with foods that have a low glycemic index being especially recommended. Stress management also plays an important role.