Why do I gain back weight after losing it, and how can I keep it off?

Have you ever intentionally lost weight, only to find that the pounds start to return? And when they do, have you found they’re much harder to shed the second, third, or fourth time around? This phenomenon, commonly known as the weight loss-regain cycle, or “yo-yo dieting,” is a frustrating reality for many people. 

Turns out, long-term weight change is more than a matter of willpower. Your metabolism plays a big role — and the good news is, you can do something about it.  

In this article, we’ll dive into the science behind weight loss and gain, exploring the factors that contribute to this cycle. We'll also provide practical strategies for sustainable success.  

Understanding the metabolic implications of weight loss 

Achieving weight loss typically involves creating what is called an energy deficit or calorie deficit, meaning you burn more calories than you consume. 

However, this simple idea hides how complex the body’s metabolism can be in response to these changes. When someone begins aggressive calorie restriction or a rapid weight loss plan, they may unwittingly trigger a series of metabolic adaptations that can hinder long-term success.  

A key reason for regaining weight is the body’s ability to adapt to changes in energy availability. When faced with a long-term calorie deficit, the body enters a state of metabolic conservation, slowing down various processes to conserve energy. ¹

One of the most notable adaptations is a reduction in your resting metabolic rate (RMR), the amount of energy you expend at rest. This means that over time, you may find you must consume fewer and fewer calories to maintain your weight, making weight maintenance increasingly challenging. 

Additionally, rapid weight loss often results in the loss of muscle mass. Unlike fat tissue, which doesn’t burn many calories at rest, muscle tissue is highly metabolically active. This means it burns a significant amount of calories, even at rest. ² 

Healthy muscle tissue also uses glucose. As a result, a reduction in muscle mass can have negative effects on your metabolic health, such as impairing glucose metabolism and further reducing your BMR. ³ 

Lessons from ‘The Biggest Loser’ study 

One of the clearest examples of these metabolic challenges comes from a study following contestants from the popular TV competition show “The Biggest Loser.” In this program, people with overweight or obesity competed to see who could lose the most weight in 30 weeks. 

Despite achieving dramatic weight loss during the show’s filming, many participants experienced a profound metabolic slowdown in the years following the competition. 

Researchers found that after six years, their resting metabolic rates (RMR) plummeted, by as much as 700 calories per day. This means that to maintain their lower weight, these contestants had to eat 700 fewer calories than someone of the same weight who had never undergone that much weight loss. This reduction in RMR made weight maintenance exceedingly difficult, with all but one of the contestants in the study regaining the weight they lost (and some gained even more). ⁴ 

These findings show how important it is for sustainable weight loss strategies to prioritise metabolic health over rapid results. While crash diets and extreme calorie restriction may bring short-term success, they often come at the expense of long-term metabolic health, setting you up for a high likelihood of weight regain.  

6 tips for sustainable weight loss 

Some lifestyle habits can boost your metabolic rate and support you in managing your weight in the short- and long-term. 

While your body needs to be in a calorie deficit to achieve weight loss, the source of these calories and how you achieve that deficit are also important. There are healthy and sustainable ways to approach this without derailing your metabolic health.  

1. Prioritise protein 

Protein is a powerhouse macronutrient that you need to build hard-working and vital muscle tissue, and consuming adequate amounts can help you lose weight.  

Protein is the most satiating of all three macronutrients, which means you’ll feel fuller after eating it compared to carbs or fats. ⁵ Your body also burns more calories digesting and processing protein than it does carbs or fat. ⁶ 

Most adults need to eat at least 100 grams (g) of protein per day (based on a goal of eating 1.5 g per kilogram of ideal bodyweight). Aim to start your day with at least 30 g at your first meal. 

2. Strength train 

Exercise burns calories, but that’s not the only reason to fit it into your routine. Strength training has specific benefits for weight loss through increasing the main tissue that drives metabolism: muscle. ^{2, 3}  

Not only does resistance training promote the creation of new muscle tissue, but it also increases your muscles’ ability to use fat and carbohydrates.    

3. Avoid ultra-processed foods 

Ultra-processed foods tend to come in a package and contain mostly refined grains, added sugars, and processed fats. 

Eating too many ultra-processed foods over a long period of time can not only derail weight-loss efforts, but also lead to associated health issues such as cardiovascular disease and type 2 diabetes. ⁷

Go for whole or minimally processed foods as close to their natural state as possible when you can. Prepare most of your meals at home using fresh or frozen ingredients.   

4. Swap your sugary beverages 

It’s easy to drink an abundance of calories if you’re not careful. Coffee orders with extra sugar or sweetened milk alternatives (we’re looking at you, oat milk) can spike your glucose and tack on extra calories from refined carbs. 

Try your coffee black or with just a splash of milk. Swap sugary beverages like soda or lemonade for plain sparkling or fruit-infused water.   

5. Customise your plate 

We all respond differently to various foods, so it’s essential to acknowledge that a “balanced” plate may look different for everyone. Instead of following a one-size-fits all approach, personalise your meals to suit your unique metabolism and preferences.  

While it’s important to pay attention to portion sizes, you should also consider how different foods affect not only your glucose control, but also your overall mood, energy levels, and cravings.  

Be sure to include protein, fibre-rich vegetables, and healthy fats in your meals, and see which carbs work best for you. You could choose complex carbs for steady energy release, low-glycaemic options to prevent significant glucose spikes, or only include non-starchy veg to keep your glucose and insulin lower.   

6. Embrace ‘exercise snacks’ 

Physical activity doesn’t have to be confined to the gym. Finding ways to add movement into your daily routine can significantly impact metabolic health and support weight management. ^{8, 9} 

Embrace the concept of exercise snacks, which are short bursts of activity spread throughout the day. Whether it’s taking the stairs instead of the lift, going for a brisk walk during your lunch break, or doing bodyweight exercises while watching TV, every bit of movement counts towards improving your metabolic health.  

A final note from Lingo 

Making lifestyle changes that prioritise your metabolic health is essential to break free from the weight loss-regain cycle. 

Tools like continuous glucose monitors, such as Lingo, can also offer valuable insight into your own metabolic response to food, activity, and stress. 

With this real-time glucose data, you can make informed choices that may support long-term weight management and overall wellbeing. A focus on sustainable strategies and metabolic health can help you achieve lasting success on the journey to a healthier lifestyle.  

^ALB-02690