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:

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:

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:

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:

• Stick to a reasonable rate of weight loss (anywhere between 0.5% to 1% of your body weight weekly)
• Avoid overly restrictive or unsustainable dietary patterns, such as the ketogenic diet, intermittent fasting, and paleo diet
• Make sure you strength train and eat enough protein — 1.6 to 2.2 grams per kg of body weight — to preserve muscle mass in a calorie deficit

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

• Keep your NEAT levels up by simply trying to move more throughout your day (e.g., walking to the nearest grocery store instead of driving, climbing the stairs instead of taking the lift, and getting up from your workstation more frequently)

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: