Important things to know about diabetes and weight loss

Losing even just a few kilos doesn’t just help prevent type 2 diabetes—it can also help manage it. Here’s why, plus how to get started.
Published 6 November 2022 | Updated 14 September 2023

Can losing weight help with type 2 diabetes?

Diabetes and weight loss often get tossed around in the same sentence, but there’s a key point that can easily get missed: It’s not just for the sake of more energy and better health. “Weight loss can improve insulin resistance,” says Angela Goscilo, M.S., R.D., a registered dietitian and the senior manager of nutrition at WeightWatchers®.

Insulin is the hormone released by the pancreas that helps move glucose from the blood to cells, where it’s used for energy. “One of the actions of insulin is to open up every cell in your body so that they can be fed by the glucose,” says David Marrero, Ph.D., Director of the Center for Border Health Disparities at the University of Arizona, United States, and former president for health care and education with the American Diabetes Association. “When you have more fat, the insulin has more cells it needs to open. This tires out the beta cells in the pancreas responsible for making more insulin. The result: The insulin doesn’t move as much glucose out of the blood, and blood sugar levels rise.

Losing weight kicks that whole process into reverse. “When you lose weight, you lose fat, which means you have fewer cells that need to be opened up and fed,” says Marrero. “This reduces the demand on the beta cells and improves insulin efficiency.”

This can help reduce your blood sugar highs, which can bring on other benefits. “Losing weight and having better glucose control has a real effect on how you feel throughout the course of the day, by giving you more energy and improving your sleep,” says Elizabeth Venditti, Ph.D., Director of the Diabetes Prevention Support Center at the University of Pittsburgh School of Medicine in Pennsylvania, United States.

Does losing weight help people with type 1 diabetes?

Since overweight and obesity aren’t significant risk factors for type 1 diabetes, weight loss hasn’t traditionally been part of the protocol for treating it. That thinking has now changed though, as rates of overweight and obesity have increased faster for people with type 1 diabetes compared with the general population.

That, combined with the discovery that weight loss improves glucose control, has led to the recommendation that people with type 1 diabetes with overweight or obesity lose weight to improve overall blood sugar management. “If you have type 1 diabetes and carry excess weight, it still impacts your glucose control,” says Venditti. “Weight loss will improve your insulin sensitivity the same way it would if you had type 2 diabetes.”

How much weight do you need to lose to improve type 2 diabetes?

It’s probably less than you think. Diabetes Australia recommends that adults with type 2 diabetes and overweight or obesity lose 5 - 10% of their weight and keep it off. If you’re 100 kilograms, that means losing just 5 to 10 kilograms can significantly improve insulin sensitivity—a.k.a. the body’s ability to use insulin efficiently. This should be done through healthier eating and regular physical activity, guided by a behaviour change program such as WeightWatchers.

While 5% is a great goal, benefits like improved blood sugar, blood pressure, cardiovascular health, and cholesterol can start to be seen even before you reach that mark. “All weight loss is good,” says Marrero. “You don’t have to lose 20 or 50 kilos—that’s not what we’re talking about. The insulin and glucose system is exquisitely sensitive, so the health benefits come from a much more modest weight loss. A little change is good; a little more change is better.”

Dropping 5% of your weight could also help you pare down the number of medications you have to take, or even lower the dosage, adds Marrero. (Just make sure you talk with your doctor before making any medication adjustments.)

Does where you carry your weight matter?

It might. To understand why you need to know about the two types of fat in the body: subcutaneous and visceral. The first sits between your skin and muscles—this is the kind you can pinch. The second kind, visceral, is stored deep in the belly and is considered more problematic. Visceral fat can cause fat to enter the bloodstream and collect on the walls of your arteries, which can lead to chronic inflammation and increased triglycerides—a type of fat found in the blood that increases your risk of heart attack or stroke. That link between visceral fat and inflammation is also why it contributes to insulin resistance, meaning that carrying excess weight in your belly can make it hard to keep your glucose levels where they should be.

But here’s the thing: As dangerous as visceral fat is, it gets shed as you start to lose weight. This will then help you lower blood pressure, improve cholesterol, and make insulin regulation more efficient.

While the whole WeightWatchers program is geared toward healthy and sustainable weight loss, there are a few ways you can encourage visceral fat loss. (These tips also help with weight loss overall):

  • Move more. Any kind of exercise is beneficial here: Aerobic activity has been shown to help you lose visceral fat while resistance training increases muscle mass and improves body composition.
  • Reach for protein. Fill up on lean sources of protein such as fish, poultry, and beans. In one study, people who focused on eating more protein had significantly less visceral fat than those who ate the recommended daily intake.
  • Sip mindfully. Drinking a daily soft drink is linked to higher levels of visceral fat (and it also makes it more difficult to control blood sugar). For beverages, reach for water or unsweetened iced tea more than sugary drinks.
  • Get more sleep. Make sleep a priority, since getting six or fewer hours of zzz’s nightly has been associated with larger waist measurements.
  • Manage stress. The stress hormone cortisol is linked to larger waists, and stress can also affect your eating patterns, spurring weight gain. This is a good opportunity to turn to other people with diabetes for emotional support: In a small study of Chinese adults, researchers found that people with diabetes who engage in ongoing peer support have improved self-care as well as better glycemic control over a four-year period.

Can losing weight help reduce the risk of diabetes complications?

Losing weight doesn’t just make blood sugar easier to control, it creates a ripple effect of health benefits, ultimately reducing your risk of developing a whole host of diabetes complications, including:

  • Reduced risk of vision problems: Diabetes is one of the top causes of vision loss and blindness. “Going blind is often the largest fear for those with diabetes, more than any other disability, and the more overweight you are, the higher your risk,” says Michael Abramoff, M.D., Ph.D., Professor of ophthalmology and visual sciences at the University of Iowa, United States. “When your blood sugar stays elevated, it causes damage to the retina, in the back of the eye. Over time, there may be too much scar tissue for proper vision.” By losing weight and staying on top of regular eye exams to catch problems early, you can significantly reduce your risk of blindness and may even eliminate the chances of serious vision issues, Abramoff says.
  • Reduced risk of cardiovascular diseases: Cardiovascular disease affects about a third of all people with type 2 diabetes and is a major cause of death. “Weight loss tends to improve blood pressure as well as cholesterol and triglycerides, which all have a major impact on heart health,” says David Baidal, M.D., Assistant Professor in the division of endocrinology, diabetes and metabolism at the University of Miami Miller School of Medicine in Florida, United States. The lower inflammation levels prompted by weight loss can also help prevent the buildup of plaque in your arteries, providing another heart health advantage, he adds.
  • Lower risk of kidney disease: Research estimates that up to half of all people with type 2 diabetes in the U.S. could develop chronic kidney disease, particularly older adults. Weight loss can make a big difference in whether that happens. “Excess weight causes the kidneys to work harder,” says Baidal. “Over time, this can affect kidney function in a negative way, potentially leading to kidney disease. Reducing your weight can lower your risk because your kidneys will operate more efficiently.”

Tell me more about…insulin and weight

Q: Can taking insulin, which everyone with type 1 diabetes has to do, make you gain weight?

A: Unfortunately, it can. “Injectable insulin doesn’t respond to fluctuations in glucose the same way the insulin your body produces does,” says Marrero. “So after the injected insulin has fed all of your cells, it keeps working and stores all the other glucose it can find as fat. This is one reason why it’s not uncommon for people with type 1 diabetes, who are 100% dependent on insulin, to gain 10 to 15% of their weight once they develop the disease.”

Q: Does all insulin have the same effect?

A: Yes, but in slightly different ways. “It doesn’t matter if the insulin is slow-acting basal insulin or more rapid acting insulin—if it finds more glucose than your cells need, it will try to store it as fat,” says Marrero. While rapid-acting insulin grabs more glucose at first, it’s out of your system faster. Basal insulin has a less intense impact, but stays active for much longer.

Q: Is there anything else working against someone with type 1 diabetes weight-wise?

A: “There is a catch-22 with people who have type 1, and that’s that if they get hypoglycemic (low blood sugar), they have to correct it with calories,” says Marrero. “You don’t have a choice, you have to eat something sweet to improve your blood sugar, but that can make it harder to lose weight.”

Q: Is it still possible for someone with type 1 to lose weight?

A: Absolutely. “It’s very doable, you just have to be thoughtful about it,” says Marrero. If you still haven’t switched to an insulin pump, now might be a good time to do that. “They can be more precise about how much insulin your body is going to use compared to an injection with a syringe or pen,” says Marrero. Other than that, the same rules apply as they do for anyone: Eat a healthier diet and move more. And remember: Baby steps are OK here. “You don’t need to lose an amazing amount of weight to have a big impact,” says Marrero. Whatever you do, don’t make a change to how much insulin you’re using without talking to your doctor.

How should you start a weight-loss plan for diabetes?

Pick a weight-loss plan you can live with long-term—one that’ll make healthy habits stick. “A well-structured program with close monitoring and follow-ups is essential," says Baidal. “It will demand time and effort, but if followed consistently, it can be critical for achieving weight loss and maintaining it.”

The WeightWatchers diabetes program helps you shift toward better-for-you behaviours when it comes to eating, moving, and even mindset. And it’s been shown in a clinical trial to have a positive impact on the scale, and on overall health—including blood sugar levels.*

Remember to look for positive signs wherever you can find them. “You’re already testing your blood sugar regularly, so you’re going to start to see that your glucose is more in control and that you are in a target range more often,” says Venditti. “That feedback can be motivating.”

Just make sure you connect with your doctor. Weight loss is often a key piece of the diabetes treatment puzzle, so they should be looped into your plan. They can also be instrumental in helping you set a weight-loss goal that’s meaningful and attainable—and celebrating your wins along the way.


*Based on a six-month multicenter trial. Apolzan JW, et al. A Scalable, Virtual Weight Management Program Tailored for Adults with Type 2 Diabetes: Effects on Glycemic Control. Presented at American Diabetes Association’s 82nd Scientific Sessions. 2022.