Is Excess Weight Making Your Type 2 Diabetes Worse? 


An estimated 80% to 90% of people living with type 2 diabetes (T2D) may also have excess weight or live with obesity. You might think your extra weight is impacting your diabetes or making it harder to manage—and you might be right.

Excess body fat not only increases your risk of complications from T2D, but also makes it harder for you to maintain healthy A1C levels (your average blood sugar levels over three months) and manage your diabetes.

So, what’s the connection between excess body fat and type 2 diabetes

Obesity can cause changes in adipose (fat) tissue, which can affect the function of β cells, the cells in the pancreas that produce and release insulin to control your blood sugar levels. These changes in fat tissue can lead to insulin resistance in multiple organs and decrease glucose metabolism.

Weight loss can help your blood sugar levels

If this all sounds like bad news, don’t be discouraged! The reverse is also true: research shows that losing weight can have a positive impact on your diabetes—including improved blood sugar levels. 

Two goals of your diabetes management plan could be:

  • Keeping blood sugar levels in a healthy range
  • Reaching and maintaining a healthy body weight

These two objectives are not separate: losing weight can help you optimize your blood sugar levels.

How much weight do I need to lose to see a benefit?

Diabetes Canada Guidelines on weight management suggest that losing just 5% to 10% of your body weight can improve insulin sensitivity (reduce insulin resistance) and blood sugar levels.

More good news: if you have a higher BMI (>40 kg/m2), you can expect to lose the same amount of weight with lifestyle changes than those with lower BMI levels.

Can lifestyle changes really help me lose and keep off my extra weight?

The Look AHEAD trial evaluated the effect of a lifestyle intervention on weight loss over eight years, in 5,145 men and women in the U.S. with type 2 diabetes, who had a body mass index (BMI) ≥25 kg/m2 (or ≥27 kg/m2 if taking insulin). The participants followed a program that included group sessions, structured meal plans and instructions to engage moderate physical activity, ranging from 25-30 minutes, which was a brisk walk for most people.

Most study participants stuck with the program: 97.1% were still enrolled after a year and 89.9% after eight years. On average, participants had lost 8.5% of their initial body weight after one year, and 4.7% after eight years.

So yes! Making lifestyle changes that are manageable for you can help you manage your weight long term. 

Will it work for me? 

Some may question whether these results apply to all genders and ethnic backgrounds. Because of the large population size, this study was able to evaluate the effect of lifestyle changes on weight loss in a diverse population:

  • 60% of study participants were women.
  • 37% identified as racial/ethnic minorities.
  • Participants were between 45 to 76 years old, and the average age was 58.7 years.

Results were comparable between women and men and among racial/ethnic groups:

  • Men and women lost a similar amount of weight over the eight years, with differences ranging from 0.3% (year 1) to 0.9% (year 8).
  • After one year, non-Hispanic white participants lost more weight than participants who identified as African American, Hispanic or American Indian/Other. However, after four and eight years, respectively, the average weight loss was comparable among the four racial/ethnic groups.
  • Weight losses of African Americans were among the largest reported in the literature.
  • Older participants (aged 65 to 76 years) lost more weight than younger ones, with the greatest difference (1.9%) at year 8.

On top of weight loss, these lifestyle changes were associated with many other long-term benefits, including improvements in physical fitness and physical function, quality of life and a decrease in the use of medications.

What if I’ve already tried diet and exercise and it didn’t work?

Establishing lifestyle changes alone can be difficult and hard to maintain over time. You’re not expected to accomplish this all by yourself—you and your doctor are not expected to do this alone, either. Recommendations include an interprofessional weight management program:

  • Group programs have shown better results than interventions by solo health care professionals.
  •  Qualified professionals can provide advice on appropriate serving sizes, caloric and carbohydrate intake and how to choose meals rich in nutrients based on dietary recommendations.
  • Programs and clinics dedicated to weight management can also help.

As someone living with type 2 diabetes, you know your body best but getting support will be key to your success. 

If diet and exercise alone don’t cut it

According to Obesity Canada guidelines, healthy eating and physical activity are fundamental components of successful weight management, but these changes alone are often not enough to achieve and maintain weight loss. 

Lifestyle changes alone generally achieve only a 3% to 5% weight loss, and this is often not maintained over the long term. This is also less than the 7% to 10% range, which research shows is ideal for lowering A1C levels.

Luckily, when healthy eating habits and physical activity are not enough or don’t lead to long-lasting weight loss, there are treatments that can help.

Diabetes Canada guidelines recommend:

  • Weight management medications to help you lose weight and help you manage your blood sugar levels.
  • Treatment with an antihyperglycemic agent—a drug that reduces blood sugar levels—if your A1C targets are not reached within three months of using lifestyle interventions.

If considering an antihyperglycemic agent, remember some antihyperglycemic medications can help you lose weight, others are weight neutral and some can lead to weight gain.

Talk to your doctor about medication options for type 2 diabetes that may help you lose weight  and improve your blood sugar levels. 

Losing weight is no small task, but you don’t have to do it alone. With the right team and program in place, you can enjoy the many benefits of weight loss, including better overall health and improved diabetes management.

Written By Patrick Boisvert, Posted , Updated 09/21/23

Patrick holds a B.Sc. in Biology from Dalhousie University and an M.Sc. in Human Genetics from McGill University. He has been a medical writer for 10 years and is happiest when he works on projects that can have a direct impact on the well-being of patients, such as those related to diabetes awareness and education. When not working, he enjoys hiking, running, cooking and reading fantasy novels.