Have you ever tried to lose weight and keep it off long-term?
If so, you know how difficult weight loss can be.
Getting in shape is a lifelong pursuit. It takes discipline to stay in a calorie deficit for an extended amount of time, and once you’ve hit your goal, you have to make sure you keep the weight off.
That’s not to say losing weight is impossible — if you have a good plan, it’s quite doable — but in order to succeed, you should know the challenges you’ll face throughout your weight loss journey.
For example, you may have heard about “starvation mode” — the idea that your body slows down your metabolism as you lose weight.
But is starvation mode real?
The concept makes sense: if you’re in a calorie deficit, your body thinks you can’t find food, and it slows down your metabolism so you can survive longer.
It turns out starvation mode is real. In some cases, your metabolism does slow down in response to weight loss. That kind of metabolic slowdown can cause you to hit a weight loss plateau, or even make you gain back weight.
Fortunately, there’s plenty you can do to avoid starvation mode and keep hitting your weight loss goals.
Let’s start with the question: what is starvation mode?
Starvation mode (sometimes called “metabolic damage” or “metabolic slowdown”) is your body’s natural response to calorie restriction.
When you consistently eat fewer calories than you burn, your body thinks you’re struggling to find food.
It responds by slowing down your metabolism, to maintain your fat stores and keep you from starving.
This process is called adaptive thermogenesis, and it’s a natural, healthy reaction to weight loss[*]. Back when humans lived in the wild and food was scarce, starvation mode saved lives — enabling our caveman ancestors to live off their fat stores through harsh, barren winters.
In the modern world, however, food is plentiful, and most people struggle with obesity, not starvation. When you’re trying to lose weight, adaptive thermogenesis actively works against you, and it’s incredibly frustrating if you’re trying to slim down.
The good news is that you can avoid starvation mode by tricking your body into keeping your metabolism elevated. But before we talk about that, let’s take a closer look at exactly how starvation mode works.
The calories you burn each day (your metabolism) can be broken down into four categories:
- Basal metabolic rate (BMR) - The base number of calories your body burns to keep you alive — keeping your lungs breathing, heart pumping, brain functioning, cells working, and so on.
- Thermic effect of food (TEF) - The calories it takes for your body to digest food and convert it to energy. Carbs and most fats have low thermic effects, while protein has a high thermic effect (you burn more calories digesting protein[*]).
- Thermic effect of exercise (TEE) - The calories you burn during exercise or other prolonged physical activity.
- Non-exercise activity thermogenesis (NEAT) - The calories you burn from small movements throughout the day. This includes things like fidgeting, typing, and walking to work.
Your Metabolism Changes During Weight Loss
When you lose weight, the calories you burn from each of these four categories can decrease. For example:
- Your brain sends signals to slow down digestion when you’re in a long-term calorie deficit[*].
- When you weigh less, it takes less energy to move your body (it requires less force to move 120 lbs. than it does to move 200 lbs.). As a result, your TEE and NEAT go down[*].
- When you eat less food, you burn fewer calories digesting that food. As a result, your TEF goes down.
- NEAT also decreases during weight loss[*]. You unconsciously stop moving as much — you fidget less, switch postures less frequently, toss and turn less during sleep, and so on.
- Leptin is a hormone made by your fat cells to suppress hunger. The higher your leptin levels, the more full you feel. But when you lose fat, your leptin levels go down. As a result, you get increasingly hungry the more weight you lose[*].
- At the same time, your thyroid hormone production decreases, decreasing your BMR[*].
Six calories per pound may not sound like much. But when you lose 10, 20, 50, or 100 pounds, metabolic slowdown starts to add up.
Plus, your metabolism continues to run more slowly after you hit your weight loss goal. That means if you go back to eating the way you were before you lost weight, you’ll regain the weight you lost.
Instead, you have to eat lighter indefinitely to maintain your weight loss over time.
How do you know if your body is in starvation mode?
Here are a few signs that your diet is making your metabolism slow down.
You’re Constantly Hungry
Occasional hunger is normal during weight loss. But if you’re constantly hungry on your diet, odds are you’ve gone into starvation mode.
If you’re hungry all the time, or you find yourself giving in to hunger and bingeing on a regular basis, you may be cutting calories too aggressively.
Hunger is largely hormonal. It’s controlled by two main hunger hormones: leptin, which makes you feel full, and ghrelin, which makes you feel hungry.
Leptin is made by your fat cells, so as you lose fat, you produce less leptin, and you get hungrier. On a well-designed diet, you’ll be able to manage these changes.
But if you cut calories too much in an attempt to lose weight quickly, you’ll experience a major drop in leptin, and you’ll feel ravenous all the time[*]. That’s a sign that your body is in starvation mode.
You Feel Cold All the Time
Long-term calorie restriction can cause your core body temperature to drop[*].
Burning calories produces heat. If your core body temperature drops, it’s a sign that your body is burning fewer calories because it thinks there’s a food shortage.
If you can’t get warm, you’ve either been continuously restricting your calories for too long, or you’ve set too large a calorie deficit for yourself.
You’ve Hit a Weight Loss Plateau
If you’re staying in a calorie deficit and doing your usual exercise routine but you stop losing weight, your body may be in starvation mode.
As you lose weight, your calorie needs will decrease. There’s less of you, which means your body requires less energy to function. It’s a good idea to recalculate your calorie needs after every 10 lbs. of weight you lose.
But if you’re accounting for your change in calorie needs and you still aren’t losing weight for multiple weeks, you may be experiencing metabolic slowdown. That means it’s time to change your diet.
Starvation mode can be frustrating — weight loss is hard enough without it.
But if you’re trying to lose weight and all this info has you feeling hopeless, don’t worry! There are several strategies you can use to prevent starvation mode and make sure you lose weight sustainably.
If you think you’re in starvation mode, or you want to avoid starvation mode down the line, try these strategies. Each one works well on its own, and you can also combine multiple strategies for a greater effect.
1. Focus on Gradual Weight Loss
If you try to lose weight too quickly, your body will panic and start doing everything it can to hold onto fat. This is one of the most common causes of metabolic slowdown.
- In a 2012 study, participants that were obese went on an aggressive weight loss program. Their goal was to lose a third of their body weight in 30 weeks. Most participants succeeded, which is impressive, but their metabolisms slowed down significantly more than expected[*].
- Another study found that short, intense weight loss caused a larger drop in metabolism than longer, more gradual weight loss[*]. On top of that, the people who lost weight gradually were better at keeping it off long-term.
- A third study showed that people on a steep calorie deficit showed a dramatic decrease in leptin, the hormone that makes you feel full. They were especially hungry, and their leptin levels didn’t return to normal until they overate[*]. This could explain why bingeing behavior is so common on short, intense diets.
It can be tempting to choose a crash diet, 30-day fat loss challenge, or other short-term weight loss program. You may be feeling determined in the moment and convince yourself that you can handle the intensity of a severe calorie deficit.
But short-term weight loss just doesn’t work for keeping off weight. Odds are you’ll run out of motivation and give up, get so hungry that you binge and gain back the weight you lose, or hit a weight loss plateau because your body enters starvation mode.
This is one of those times when slow and steady wins the race. Focus on gradual, long-term weight loss. Use an online calculator to figure out how many calories you burn in a day, then set a reasonable 15-20% calorie deficit for yourself.
2. Lift Weights
At rest, muscle tissue burns several times more calories than fat tissue does[*]. If you’re carrying more muscle, you’ll burn more calories, even when you’re just sitting around.
For that reason, weightlifting is a great way to counter metabolic slowdown. It can keep your metabolism high as you lose weight, making it easier for you to shed body fat.
In a 2008 study, participants all followed the same weight loss diet, but they split into three exercise groups: weight training, cardio, or no exercise.
All three groups lost weight. But at the end of the study, the weight training group lost the least muscle and kept their metabolic rate the highest[*].
The cardio and no exercise groups saw significantly larger drops in metabolism.
So if you want to guard against starvation mode, add lifting to your weight loss routine. This guide to resistance training can help you choose a solid workout plan.
3. Give Yourself a Break From Dieting
Constant, long-term calorie restriction can be hard on you, both physically and psychologically. It can also contribute to metabolic slowdown.
A better approach may be to alternate between dieting for two weeks, then taking a break for two weeks.
A famous study called MATADOR (Minimizing Adaptive Thermogenesis And Deactivating Obesity Rebound) found that this two-weeks-on, two-weeks-off approach is very successful. It led to greater weight loss with less metabolic slowdown than standard continuous dieting[*].
Participants who did the MATADOR approach were also much more likely to keep the weight off long-term.
To be clear: you don’t get to eat as much as you want during your two weeks off. You just eat at maintenance calories, to give your metabolism (and your mind) a break from the stress of calorie restriction.
This is one of the most successful approaches to weight loss. It’s a great way to keep your metabolism strong while still losing body fat.
4. Eat More Protein
Another way to prevent starvation mode is to eat more protein.
Protein is the most thermogenic macronutrient — in other words, you burn more calories digesting protein than you do fat or carbs[*].
Our protein calculator can help you figure out how much protein you should eat for weight loss or muscle building.
Starvation mode is a real thing. Your metabolism really does slow down during weight loss, and it can keep you from reaching your weight loss goals.
However, there’s a lot you can do to prevent starvation mode. A sustainable weight loss plan will help you keep your metabolism high, lose weight long-term, and keep it off once you’ve hit your goal.
If you aren’t sure where to start with your weight loss, our nutrition advice is full of simple, actionable tips to improve your health.
And if you want more insight and science on nutrition, don’t miss these resources: