Weight Gain after Weight Loss: Why It Occurs and How to Prevent it

This post is written by Osama Hamdy, M.D., Ph.D., Medical Director of the Obesity Clinical Program and Director of Inpatient Diabetes Management at Joslin Diabetes Center and Assistant Professor of Medicine at Harvard Medical School. Dr. Hamdy is also the Director of the Why WAIT program where he works with people to improve their diabetes management through weight reduction.

A recent article in the New York Times details the disappointing weight regain among several contestants of the popular show, “The Biggest Loser.” The Times finds that the contestants either regained all of the weight lost following the show, or in some cases regained more weight than they lost during the show. These findings have triggered curiosity and concern among many people embarking on their own weight loss journey, prompting questions such as: Will I regain all of the weight I have lost? Am I at risk to regain the weight? And how can I prevent regaining the weight?

BMI Cutoff for Optimal Weight Loss

Several years ago, the team of the Why WAIT program at Joslin Diabetes Center, which is a 12-week multidisciplinary program for weight control and intensive diabetes management, was looking for the best predictor for whether program participants would regain weight following weight loss. We found that people with initial BMI of 45 Kg/m2 or higher who lost weight are more likely to regain most of that weight back.

And here’s why – in people with a BMI of 45 Kg/m2 or higher, their bodies frequently shut down their satiety hormone “leptin” after significant weight loss as seen in the Biggest Loser contestants, and instead increases their hunger hormones, causing them to struggle with maintain weight loss under the effect of intense hunger. This complex physiologic and hormonal process makes people with a higher BMI more susceptible to weight regain. Therefore, the best option for people at that weight level is to undergo bariatric surgery.

However, people at a lower BMI of 25-45 Kg/m2 are good candidates for weight loss via diet, exercise and behavioral intervention as research shows they are able to maintain weight loss or only regain part of the weight lost.

Why WAIT Proves that Long-Term Weight Loss is Possible

In the Why WAIT program we followed hundreds of participants and found that they were able to maintain 6.4 percent weight loss after 5 years.  Around 53 percent maintained a weight loss of 9 percent for five years.  The other 47 percent did regain some weight but maintained their eventual weight at around 3.4 percent weight loss at five years. We observed that those who lost and maintained 7 percent weight loss at one year are more likely to maintain the weight loss in the long-term. The full results were presented in 2015 at the American Diabetes Association (ADA) conference in Boston.

Muscle Mass is at the Heart of Long-Term Weight Loss

why_wait (390)This brings us to the question of why do some people who start at a BMI lower than 45 maintain their weight loss while others do not?  The answer to this lies in the amount of muscle mass that people lose when they lose weight.

When a person loses weight, usually 25-27 percent of the total weight lost is from lean muscle mass, which means if you lose 10 pounds, approximately 2.5 pounds of that loss from your muscle mass.  And, that has a big effect on your metabolic rate.

Muscles are the most prevalent mass in your body, and they are the largest consumer of energy in your body, especially during rest. The amount of energy/number of calories your body consumes in a resting state, like sleeping, is known as your basal metabolic rate. That’s the amount of energy/calories your body is consuming in the background all time – which is important because that accounts for 60 to 75 percent of the all the energy/calories you consume each day.

Your metabolic rate can and does change.  Muscle builds up over many years, driven by hormones, such as growth hormones, sex hormones and insulin. As you age the hormones that drive muscle development, decrease. People without diabetes lose around 300 grams of their muscle mass every year after the age of 40, and people with diabetes lose around 400-450 grams of muscle mass, or around one pound per year.  This is why it is harder to lose weight as you age.

Likewise, when you lose weight, your basal metabolic rate will go down (remember: 25-27 percent of the total weight lost is from lean muscle mass needed for basal metabolism).  As you continue to lose weight, you continue to loose muscle mass, thus further decreasing your basal metabolic rate.

So what does this mean for your weight loss progress? This means that because you have lowered your basal metabolism, you are at risk of eventually reaching the point where you will regain weight back, even on a low calorie diet. And when you regain weight, unfortunately, you don’t get the muscle back; what you get is mostly fat. And with every subsequent attempt to lose weight, you lose more muscles and gain fat back. This is what is called Yo-Yo weight.

How to Prevent Long-Term Weight Regain

Regaining weight that you have worked hard to lose is what frustrates so many people.  The question is how can you prevent this from happening? The answer is simple – prevent the loss of muscle mass by increasing protein in your diet and doing anaerobic exercise.

The problem with many commercial weight loss plans is that they do the opposite.  They start with a low calorie and low protein diet, where protein only makes up 15 percent of the food plan. Then they exacerbate muscle loss by combining that low protein diet with aerobic exercise, such as running or cycling. Unfortunately, this kind of weight loss strategy is very popular, but it is also very risky.  There is very little scientific basis for these weight loss plans, and they carry a high risk for regaining the weight.

The Why WAIT Approach

The Joslin Why WAIT program is a unique model for long-term weight loss that is scientifically designed to help people both lose and maintain their weight loss.

In the Why WAIT program, we measure body composition and provide protein intake at 1.5 gm/Kg body weight irrespective to the caloric level used, which provides enough protein to maintain muscle mass. We also couple this diet with strength training.

With this strategy we have been able to reduce muscle mass loss to only 11-13 percent of the total weight lost, and also increase lean mass/fat mass. Our research shows that, if people continue with strengthening exercises, they are likely to maintain a higher metabolic rate after their initial weight loss.

As shown in the study presented at ADA Scientific Sessions, the experience of the evidence-based Why WAIT program proves that these techniques help maintain weight loss for a longer duration of time.

To enroll in Joslin’s Why WAIT program or for more information, click here.

This article was first published on June 16, 2016


  1. Thank you so much for posting this article! I am a yo-yo Type I Diabetic that can’t lose weight no matter what I try!! I will send a note in to find out about this Why Weight program.

  2. Very interesting. Two years ago I lost 20 lbs using walking and calorie counting. The next year I put 10 of it back on. I recently lost 8 of that 10 following the “Fast Metabolism Diet”. I am happy to see the FMDiet is very compatible with the approach you describe in this article. Makes me hopeful for the future. I have 10 more I want to lose and then keep it all off.

  3. Thanks very good article While focused on wait loss I was very sucessful in lossing 50 pounds. Once there I found it easier to convince myself that perhaps I need not be so focused and a little slip fromm time to time lead back the the “trouble zone “. It all makes sense, I will definently be back at itand will loose 60 pounds this time !! Hey who’s the guy with the great mustache ?

  4. Excellent article.
    Would like information with respect to pediatric obese patients and teenagers and STRENGHT TRAINING.

  5. Thank you for sharing. I’m a Type ll -yo-yo. But those days are over for me. I have discovered the secret(S) of Weight-Loss. I am experimenting on myself. My program is targeted at males, age 50- 60, with an initial BMI of 30- 35. Myself, l initially weighed 235 lbs. In 60 days, I will lose -50 lbs. One of my main drivers (among other things) in shedding these pounds is “Anaerobic Exercise”. Building lean muscle mass on the way down minimizes the rebound of regaining weight and creates a stable environment for maintaining the weight loss that people work so hard to achieve. My A1c is presently 6.5. I have no idea where it will end up -50 later. However l can’t wait to find out.

  6. This article should be given to every Type 1 diabetic with a weight issue. After spending most of my adult life at 200+ pounds and losing only small amounts of weight (less than 10%) or gaining the weight back in less than two years on diet plans or doing cardiovascular workouts, I started working out with a trainer once weekly (as well as 2-3 times on my own) about 16 months ago. During that period, I lifted heavier and heavier weights with some aerobic exercise, watched my diet a little closer, and kept lowering my basal rates (after a couple of bad reactions at night), resulting in a monthly average weight loss of a pound or less. Have lost about 18% of my body weight, have great stamina and strength (push repetitively over 500 lbs with my legs), have A1Cs of about 6.5 (always good but closer to 7 before), and increased Vitamin D and lowered lipid blood levels. Would like to achieve another 7-10% loss (from original level) over the next year with increased exercise and diet adjustment.

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