HbA1c and Weight Loss

It’s long been established — based on both research studies and real-world clinical experience — that in many people with Type 2 diabetes, losing weight can help control blood glucose levels. In fact, one of the very first posts here at Diabetes Flashpoints was a personal account of losing weight and reaching a lower HbA1c level (a measure of long-term blood glucose control) on a low-carb diet.


But different studies over the years have focused on different populations of people with Type 2 diabetes, some of whom had higher HbA1c levels or were more overweight or obese than others. So in a study published last month in the journal Diabetes, Obesity and Metabolism, researchers sought to combine the results of several studies to find out whether there’s an overall pattern to how much HbA1c levels can be reduced by losing weight. They found 58 studies that met their criteria, conducted between 1990 and 2012, in which overweight or obese people with Type 2 diabetes lost weight through reduced-calorie diets, weight-loss drugs, or bariatric surgery. In these studies, a total of 17,204 people were followed for between 3 and 24 months after beginning their weight-loss intervention.

As noted in an article on the study at Physician’s Briefing, the researchers found that overall, there was a linear relationship between weight loss and HbA1c reduction. Specifically, the average person saw their HbA1c drop by 0.1% for each kilogram (about 2.2 pounds) of body weight lost — regardless of whether it was the first or last kilogram of weight loss over the course of the study. But that’s doesn’t mean this average applied to everyone — in fact, people with a higher starting HbA1c level saw a bigger drop in HbA1c for each kilogram of body weight lost, compared with those who started at a lower HbA1c level.

This study shouldn’t be considered definitive, and its researchers conclude that its results should be used to help design future studies on how weight-loss interventions can help manage Type 2 diabetes. But the results strongly suggest that the higher your HbA1c level, the more you have to gain, so to speak, by losing weight. This means that someone who is overweight, but not obese, and has a very high HbA1c level might benefit more from weight loss — at least in terms of diabetes control — than someone who is obese but has only a slightly elevated HbA1c level.

What’s your experience regarding weight loss and blood glucose control — have you ever lost weight and experienced a lower HbA1c level as a result? If so, how high was your HbA1c to begin with? Did your lower HbA1c last, whether you maintained the weight loss or put the weight back on? Do you think it’s realistic to make weight loss a major component of diabetes management, or are there better, more reliable ways to achieve lower blood glucose levels? Leave a comment below!

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  • Samwell Baggins

    My diagnosis A1c was 7.3, and I got this down to 5.5 ten weeks later with a 15-pound weight loss and elimination of pizza, all-you-can-eat buffets, sweet tea and any soft drinks. Following a further 50-pound weight loss in five months, my A1c dropped to 4.8 with strict diet control and crazy exercise.

    My doctor credits the improvement in A1c more to my diet change and not so much the weight loss, but I am sure the weight loss had everything to do with lowering my insulin resistance and my A1c. Common sense tells me that getting rid of the visceral fat and fat everywhere else was a good health move on my part. With a less restrictive diet, my A1c remains firmly at 5,1. I have kept off 60 of the 65 pounds I lost, look better and feel better with resistance training and interval training.

    • Arnold Saenz

      Am curious about your age?

    • Lil25

      Exercise DRASTICALLY reduces insulin resistance. Weight loss probably helps, but I’m guessing all that exercise is what made the most difference.

      • Hank Haney

        In my case, I exercised a lot, and I doubled exercise to lose weight. My improvement was all weight loss. You simply must STOP EATING. Eating is worse for most than is smoking.

  • Karen Hayner

    Can you give me your opinion about my situation? I am a 47 year old female. Over the past 3 months I have fairly drastically improved my diet and reduced consumption of carbs in the form of sweets as well as bread, pasta, rice, potatoes but not completely cut them out. I generally eat no sweets, baked goods, or candy and only eat a serving of bread, pasta, or potatoes a couple times a week. I eat two servings of fruit a day, sometimes only 1. All Carb foods are carefully portion controlled. I have increased exercise and spend 45 min to an hour a day 6 or 7 days a week doing cardio and strength training.I have lost 28 pounds reducing my BMI from 36.9 to 31.6. I’m still obese but getting closer to overweight range. I recently have hit a bit of a plateau having not much weight change in the last two weeks but still continuing my healthy ways. My A1C in April 2017 at a BMI of 36.9 was 5.4 and today at a BMI of 31.6 was 5.7. I am very upset about this and do not understand how this could be. Any thoughts?

    • Amanda ZZ

      you do not say where you started from ?

    • Hank Haney

      You simply must cut out all carbs. Returned my A1c to normal after losing 25 pounds and doubling my exercise. You simply must make food “in the past,” and become “carb celibate” (of course you will still get some), but 90% of my diet is leafy vegetables, and then lean meat, nuts, and just enough fruit for nutrition (fruit is too sugary). You must put food “in the past” as something to enjoy.

  • Norman Summerfield

    When I was 50 my BGL rose quickly to over 35 and I began to have cloudy vision. I started eating less sugary foods and less food altogether. I decided to begin running regularly and soon got a puppy and ran him for miles. He really enjoyed that and I was soon able to let him off the lead. After a few weeks my BGL was always under 10 and could easily drop below 4. I am not sure when, but my normally 20/10 vision returned. Although my GP had written ‘diabetic’ in my records, I asked him if I could have had an illness, so he sent me to two glucose tolerance tests, which I passed. Diabetic medication was not indicated, since I had a BGL of around 5 on average after dropping from 15 st to 13 st. I am deliberately losing weight again, since my BGL has risen somewhat, although not to 35 or anything near that. After losing a few pounds, I am getting lower BGL readings. I had tried Metformin for a year or so, but after stopping it I realised that the joint pain I previously attributed to growing older was gone.

  • Paul

    OK … so, I’m a 56 year old man, 5’11 and four months ago weighed 216#. I was horrified to see a fasting blood sugar of 127 and triglycerides over 400. Over three months I lost weight with a 1600 calorie diet and exercise. Today I am down to 175# and my fasting blood sugar last week was 107, my HA1C was 5.6 and my triglycerides were normal. My doc said I don’t need meds and will be rechecked in six months. I’d like to lose maybe another 5# then focus on maintaining that weight and increasing exercise.