You're probably not experiencing 'starvation mode' if your weight loss has stalled — here's what could be happening instead
- Registered dietitian Jennifer Low told Insider that starvation mode, the idea that if you eat too little you'll stop losing weight because your body will hold on to its fat stores, is stricly a "a survival mechanism."
- "If you reduce your energy intake too much, your body slows its metabolism in response to this," she said. "It wants to maintain its weight."
- The concept is widely misunderstood when it comes to most people's weight loss efforts, according to personal trainers Jordan Syatt and Emma Storey-Gordon.
- When people drop their calories too low, a few days of extreme restriction leads to overindulgence, thus undoing the calorie deficit.
- In extreme cases, true starvation mode can occur, but it's unlikely the majority of people will experience this when trying to lose fat, registered nutritionist Rhiannon Lambert explained.
When trying to lose weight, it's often suggested that you shouldn't drop your calories too low, because your body will go into "starvation mode" and hold on to fat.
The idea is that if you stop eating or don't eat enough, your body will do everything it can to preserve energy, including holding on to the weight you're trying to lose.
While the concept of avoiding crash dieting and severe restriction is important, it turns out "starvation mode" is probably not the reason your weight loss efforts have stalled, unless you're extremely malnourished.
In reality, there are many factors at play when people think they're in starvation mode and not losing fat as a result.
Insider spoke to a dietitian, a registered nutrionist, and two personal trainers and fat loss coaches to find out what's really happening, and what you need to do to achieve your weight loss goals in a healthy way.
Starvation mode exists, but not as most people understand it
Registered dietitian and spokesperson for the British Dietetic Association Jennifer Low told Insider that starvation mode is "a survival mechanism."
"If you reduce your energy intake too much, your body slows its metabolism in response to this," she said. "It wants to maintain its weight."
Low explained that she has seen people following fairly extreme calorie reduction diets in a bid to lose weight, becoming lethargic and exhausted, growing frustrated with the scales, and then falling into the yo-yo dieting trap.
But a ccording to registered nutritionist Rhiannon Lambert, true starvation mode only occurs in cases of extreme malnourishment, such as when someone is suffering from an eating disorder.
"When the body is starved of calories or energy, your muscle mass then declines as well in turn," she told Insider.
"And of course with the lower amount of muscle mass, your metabolic adaption is changed. So when your metabolic rate declines, you don't require as many calories and you stall any weight loss, your body is just trying to cling on to what it can in order to survive."
Lambert said starvation mode is a confusing term, because although it isn't a made-up concept, it's not something the vast majority of people are experiencing when their fat loss progress plateaus.
"[Starvation mode] occurs in people that are severely, severely malnourished and that have burned all their fat away," she explained.
"Now they're burning away at the muscle, that tends to be the situation in which it's used."
Lambert said this is why you shouldn't try and lose more than two pounds of weight a week, as any more than that is "ineffective."
"Your body's very clever, it will adapt to a period of famine where it will preserve fat stores rather than burn them," she said.
"But like I said, for most of us, it's very, very unlikely we would be putting our body into that type of state. It's a very, very extreme situation."
The now infamous Minnesota Experiment makes this clear: It saw 36 male conscientious objectors during World War Two volunteer to take part in a semi-starvation study where their calories were dropped to around 1,800 for six months (following three months at 3,200 calories), and they were asked to expend 3,000 a day.
It wasn't until the men reached extreme levels of leanness with body fat levels of about 5% that they stopped losing weight, because they would have died if they lost any more.
'No one has ever gained fat from eating too little'
Although starvation mode is real, it's not something the average person encounters when trying to lose weight. You don't go into starvation mode from, say, skipping a meal, fasting for 24 hours, or just dropping your calories a bit too low for a few days.
Fat loss coach and personal trainer Jordan Syatt describes the concept of starvation mode as "completely and utterly stupid" when it comes to most people's weight loss efforts, adding: "That is not how the body works."
Syatt maintains that eating too little certainly is not advisable, but he told Insider that you only need to look at people throughout history who have been severely underfed due to awful conditions to prove that the concept, as most people think it works, doesn't make sense.
"There's never been a prisoner of war who came out of being a prisoner overweight," Syatt said.
While Syatt stressed that it's important not to under-eat in order to maintain a healthy plan you can stick to, he added that for most people, they won't start holding on to fat because they're eating too little.
Personal trainer and fat loss coach Emma Storey-Gordon, who holds a degree in sports and exercise science, echoed Syatt's sentiment.
"The starvation mode myth is essentially the notion that you can eat too little to lose weight, meaning you would have to magically store calories you haven't consumed," she told Insider.
"On a physiological level this simply isn't true. The crudest example is that if starvation mode did occur then no one would starve."
You need fewer calories as you lose weight
To lose weight you need to be in an energy deficit (ie. consuming fewer calories than you burn over the course of the day).
As you lose weight, there's less of you, so you require fewer calories, a concept referred to as metabolic adaptation.
"As you go deeper into a deficit, your metabolism will slow down. That's a normal human response to a caloric deficit," Syatt explained.
Studies prove this point and show that it works in reverse, too; when you start to eat more, your metabolism gets a boost, but if you're in a calorie surplus instead of a deficit, you could still gain weight.
"People hear that your metabolism goes down from being in a calorie deficit and they think that must mean you should never go into a calorie deficit," said Syatt.
"Well, that's not true. If you want to lose fat, you have to be in a calorie deficit. If you're eating in a calorie surplus, even though your metabolism is higher, you're still in a surplus, so you're still going to gain body fat."
You still shouldn't drop your calories too low, however
If you want to lose fat sustainably, your calorie deficit needs to be small enough that you can stick to it and still enjoy your lifestyle.
If you restrict yourself and drop your calories too low for five days, the chances are every weekend you'll feel the need to go wild. In just a couple of weekend blowout meals (especially with drinks), it's very easy to undo the calorie deficit you created in the five days leading up to it.
If you're not losing weight when you're sticking to your strict calorie target most days, these binge sessions could be the reason.
"I have a lot of clients coming to me saying they are not losing weight despite being on very low (always seems to be 1,200) calories," Storey-Gordon told Insider.
"What is actually happening is that they are over-restricting so much that they inevitably end up over-indulging and eating way over their calories every few days, which means that on average, over time, they are not in a deficit and thus are not losing body fat."
She added: "The answer here isn't to try to avoid the over-indulgence, which is where most people focus, but to stop the over-restriction.
"Bringing calories up to something manageable means that you can actually stick to those calories, create an energy deficit over time, and force the body to use its fat stores for energy. That is how you lose fat!"
Syatt agreed, stressing that eating too little is unsustainable in the long-term, precisely because it drives overeating episodes.
"If you take a more sustainable approach, it's significantly better long-term physiologically and psychologically as well," he said.
Don't be fooled by the scale
Syatt told Insider another way people go wrong is by equating the number on the scale — their weight — with their body fat.
In reality, your weight will fluctuate massively depending on when you last ate, what you ate (salty foods, for example, cause water retention), and other factors, including where a woman is in her menstrual cycle.
"If you associate your weight with body fat, when the scale spikes up, you think you must be gaining weight too," Syatt explained.
"When the scale doesn't change, you think your calorie deficit must not be working. You [think you] must be in starvation mode."
Syatt said this leads to people giving up, when actually if they'd just remained consistent, the scale would have dropped back down again in a few days.
You may be moving less without realizing
Storey-Gordon said one thing people don't realize when they're in an energy deficit is that they're naturally moving less over the course of the day, known as adaptive thermogenesis. This can lead to burning fewer calories, and therefore not losing as much weight.
"What people may not notice is the reduced energy expenditure," she said. "This is via things like reducing NEAT (non-exercise activity thermogenesis), which is a fancy way of saying how active you are."
NEAT is essentially movement you do that isn't formal exercise, such as walking up stairs, cleaning, or carrying shopping. When you have less energy due to eating less, it's normal to move less subconsciously.
Numerous studies have proven that adaptive thermogenesis is real, so when you think your body has entered starvation mode, it could actually just be that you're moving less without realizing.
"You also become more efficient and expend less energy doing the same activity," Storey-Gordon said.
"As you lose weight and become a smaller person, your resting metabolic rate drops (the calories you expend just lying in bed), and you require fewer calories."
The more weight you lose, the slower your progress will be
A comprehensive review of 90 studies found that the quicker you lose weight (a two to six week diet or "cut" compared to a longer time spent in a smaller calorie deficit), the more your metabolic rate will drop.
It's also worth bearing in mind that your progress will likely slow the further you get down your fat loss journey.
"It is important to know that your metabolism does drop from being in a calorie deficit, but it's not inherently bad," Syatt told Insider.
"It's just a normal human physiological response that as you're losing weight, your body requires less energy in order to live. So your metabolism drops, you're burning less, you're using less energy.
"That's just normal in the same way that when you're gaining weight, your metabolism is increasing, but you don't want to add calories, you don't want to eat more just to increase your metabolism because you'll end up gaining weight."
Metabolic adaptation isn't a problem to be "fixed," it's just what happens.
However, you can keep your metabolism as high as possible by focusing on strength work and making sure you eat enough protein.
"Resistance training to build and maintain muscle mass and adequate protein consumption can help offset some metabolic adaptation," Storey-Gordon advised.
An often-cited study compared three groups of people who were all put in a calorie deficit. One group was told to resistance train, the second to do cardio, and the third to do no exercise.
People in the resistance training group were found to maintain their metabolic rate, strength, and muscle, unlike those in the other two groups.
Equally, research suggests that eating adequate protein can help keep your metabolism up when in a calorie deficit.
"In general, long-term fat loss is about creating good habits like exercising, being active, and eating a balanced diet in accordance to your energy needs," Storey-Gordon said.
The key is to think long-term.
Dietitian Low advises listening to your body to work out what healthy means to you.
"If you're restricting your food intake, you may be slowing your metabolism, making social eating more difficult and setting yourself up for a lifetime of weight yo-yo-ing," she said.
"Also remember, it is not normal for us to all be aspiring to be a size 6!"
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