Is Your Diet Setting You Up for Future Weight Gain?

Go on a diet and you'd ... gain weight? Sometimes even more than you've lost? Find out why this happens and, more importantly, how to prevent it.

An illustration of an overweight person sitting in his room playing on his phone and having a feast

Step 1: notice that your body weight is a tad (or maybe a lot) higher than you’d like.

Step 2: go on a diet.

Step 3: lose weight.

Ah, happy ever after, right?

No. As it turns out, many people run into a Step 4: gain all the lost weight and then some more — essentially making them "fatter" than before the diet.

Um. So, what even is the point of going on a diet in the first place? 🤷

End your diet and expect weight gain?

How can a diet cause weight gain? It’s just a joke, right? The research paints a clear picture:

1️⃣ 2007 review published in The American Psychologist: Showed that at least one-third of dieters regained more weight than they lost on their diets.

2️⃣ 2016 review published in Clinical Obesity: Found that individuals with a more extensive history of dieting attempts tend to gain more weight throughout their life and weigh more later in life.

3️⃣ 2019 study published in Obesity Science and Practice: During the follow-up examination 11 years later, researchers found that individuals who attempted to diet during the initial survey reported significantly greater body mass index (BMI) and waist circumference increases than non-dieters.

Understanding the post-diet weight gain

But … how can a diet make you fatter?

Well, 2 different changes play a hand in the puzzling (and frankly disheartening) phenomenon: 1) physiological and 2) psychological changes.

If you’re a long-time reader of GymStreak’s blog, you’d know that we’ve talked about post-diet physiological changes — or, in other words, “metabolic adaptations” — at length.

So, feel free to skip ahead or skim the following section, which was written to get those new here (👋 hello, and welcome!) up to speed.

So, when you diet, you’d lose:

  • Body weight: Eat in a calorie deficit (i.e., fewer calories than your body burns), and you'll lose weight. But that calorie deficit won’t be enough to sustain continued weight loss. To illustrate, let’s assume you weigh 70 kg and your maintenance calories = 1,700 calories. You’re sticking to a calorie deficit of 200, which means you’re eating 1,500 calories. As you get closer to your goal weight, your maintenance calories decrease — which means your calorie deficit gets closer and closer to 0. So, to continue losing weight, you’ll likely need to eat <1,500 calories.
  • Muscle mass: Not all the body weight you lose will come from fat. Some of it will come from precious, precious muscle mass. And unfortunately, research shows that the more muscle mass you lose, the hungrier you tend to be (because muscle mass plays an important role in appetite regulation). Meaning? Good luck trying to stick to your calorie deficit.
  • Enthusiasm for moving: Weight loss fatigue is real. And when you’re so tired all the time, you won’t feel like moving, which translates to a significant reduction in your non-exercise activity thermogenesis (NEAT) levels. So, imagine if you thought your maintenance calories were 1,500 — when, in truth, it's 1,300 because you're basically living like a sloth (FYI, at the risk of stating the obvious, NEAT counts toward your total daily energy expenditure)!

Want to learn more about metabolic adaptation? Then check this article out:

Can Weight Loss ‘Damage’ Your Metabolism?
There’s much discussion on metabolic damage: the idea that weight loss could slow down your metabolism - forever. Should you be worried about it?

As for the psychological changes?

According to a recent 2023 systematic review published in The British Journal of Nutrition, it seems that individuals are more prone to experiencing adverse psychological outcomes — such as low self-efficacy, self-blame, and disordered eating patterns — that promote post-diet weight gain when they:

🧠 Implement rigid cognitive restraint

🍲 Adhere to inadvisable, overly restrictive diet strategies

🌀 Have pre-existing predispositions to weight gain, disordered eating symptoms, or negative self-image

How to prevent the post-diet weight gain

Before you give up on the thought of dieting ("Omg, it'll make me even fatter than I am now!"), please know that post-diet weight gain doesn’t happen to everyone.

Take this 2014 study published in the American Journal of Preventive Medicine, for instance. The researchers found that 87% of participants maintained at least a 10% weight loss after 5 and 10 years.

And the lessons you can learn from these individuals who’ve successfully lost weight — and kept it off? There are a few:

Struggling to eat enough protein? Find inspiration in these (🤞):

Getting Your Protein In on the Cheap (Source and Meal Ideas)
Find out how you can hit your daily protein requirements on the cheap - including source, seasoning, and even meal ideas. Pack those muscles on.
How To Create Delicious Meal Plans for a High Protein Diet
There are countless meal plans suitable for a high-protein diet. But? None show you how to tailor recipes to your needs. So, let’s change that.
How To Create Delicious Vegan Meal Plans You’ll Want To Eat
There are countless vegan meal plans out there. But? None show you how to tailor recipes to your unique fitness goals. So, let’s change that.

Disclaimer: these strategies primarily target the physiological changes associated with dieting.

If you have predispositions to disordered eating or body image issues, you may consider linking up with a health professional, such as a dietitian or psychologist, who could safely guide you through the dieting process.

Need help with your fitness and nutrition plan?

Ultimately, successful long-term weight loss maintenance comes down to 2 things: your nutrition and fitness. And now, if you’d like tailored fitness and nutrition plans that’ll help you lose weight and keep it off (because we all know using ChatGPT won’t cut it), do check out GymStreak.

Here’s a sneak peek of what it could do for you:

Workout Programming + Nutrition Tracking, Off Your Hands

*sigh of relief* We'll guide you through it all — step-by-step. Just download the app, and you'll be making progress toward your dream body like never before.


Dulloo, A. G., Miles-Chan, J. L., & Schutz, Y. (2018). Collateral fattening in body composition autoregulation: Its determinants and significance for obesity predisposition. European Journal of Clinical Nutrition, 72(5), 657–664.

Mann, T., Tomiyama, A. J., Westling, E., Lew, A.-M., Samuels, B., & Chatman, J. (2007). Medicare’s search for effective obesity treatments: Diets are not the answer. The American Psychologist, 62(3), 220–233.

Montesi, L., El Ghoch, M., Brodosi, L., Calugi, S., Marchesini, G., & Dalle Grave, R. (2016). Long-term weight loss maintenance for obesity: A multidisciplinary approach. Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy, 9, 37–46.

Pélissier, L., Bagot, S., Miles-Chan, J. L., Pereira, B., Boirie, Y., Duclos, M., Dulloo, A., Isacco, L., & Thivel, D. (2023). Is dieting a risk for higher weight gain in normal-weight individual? A systematic review and meta-analysis. The British Journal of Nutrition, 1–23.

Sares-Jäske, L., Knekt, P., Männistö, S., Lindfors, O., & Heliövaara, M. (2019). Self-report dieting and long-term changes in body mass index and waist circumference. Obesity Science & Practice, 5(4), 291–303.

Schaumberg, K., Anderson, D. A., Anderson, L. M., Reilly, E. E., & Gorrell, S. (2016). Dietary restraint: What’s the harm? A review of the relationship between dietary restraint, weight trajectory and the development of eating pathology. Clinical Obesity, 6(2), 89–100.

Thomas, J. G., Bond, D. S., Phelan, S., Hill, J. O., & Wing, R. R. (2014). Weight-loss maintenance for 10 years in the National Weight Control Registry. American Journal of Preventive Medicine, 46(1), 17–23.