When you gained weight, the problem was that you were eating too much. But when you’re trying to lose weight, the problem can sometimes become that you’re not eating enough.
Yes, really: Eating too little can slow your metabolism down. When you take in dramatically less energy than your body needs, your body can slow down how much fuel it uses, meaning you burn off far fewer calories than normal, which can sabotage your weight loss.
And eating too little can have other consequences on how your body functions, too: Certain nutrients, like Vitamins A and D, need to dissolve in dietary fat before being carried to your bloodstream. So if you’re eating too little (specifically, too little fat), your body won’t be able to use those nutrients that you do eat. And the weight you do lose won’t be the kind you’re trying to shed: According to the University of Maryland Medical Center, “extreme” dieting leads to weight loss that is 30 percent from muscle mass, not fat mass.
So how much is the right amount to eat for healthy weight loss? It depends on your weight. Your body weight determines your “basal metabolic rate,” or BMR, which is a measure of how many calories you’d burn if you did nothing at all—basically, how much energy your body needs simply to function. You can create an approximation of your BMR using the following formulas:
For men: (10 x your weight in kg) + (6.25 x your height in cm) – (5 x your age) + 5
For women: (10 x your weight in kg) + (6.25 x your height in cm) – (5 x your age) – 161
You’ve got to factor in exercise, too. If you exercise almost not at all, multiply your approximate BMR by 1.2. If you exercise 1 to 3 times per week, multiply it by 1.375. The resulting number is an approximation of your “maintenance calories”: That is, if you ate that much, you’d stay at roughly the same weight you are now.
For effective weight loss, experts recommend several ranges below your personal maintenance level. For those hoping to lose just a little weight, that range is usually around 500 calories below the maintenance number, while for obese individuals, this can rise to just over 1,000 calories below maintenance. Consistently go any lower, though, and you could sabotage your efforts.
Luckily, if you’re on the Nutrisystem program, you can feel confident that you are eating the right balance of nutrients and calories to keep you feeling great while you lose weight. But if you’re guilty of not eating all of your foods, or skipping your add ins like SmartCarbs, PowerFuels and non-starchy veggies, you just might be guilty of eating too little.
Here are six signs that you’re not eating enough:
1. Your weight loss has stalled.
Weight loss plateaus—where you’ve lost weight, and now can’t seem to anymore—can come from lots of different things: After a bit of success with strict tracking and portion control, some dieters start to get comfortable (and a little lazy) about their plan. Others forget to adjust their food intake down to match their new weight—so they’re still eating at a weight loss level for their starting weight, which isn’t as big a deficit for their current weight.
But some just aren’t eating enough. This messes with your hormones—including hunger hormones and thyroid hormones which can contribute to the metabolism slowdown. Consuming a meal that’s slightly higher in carbs and calories can have an effect on your hormones all week: It raise your levels of leptin, a hormone associated with fullness, and lower levels of ghrelin, a hormone associated with hunger. It can also re-balance the thyroid hormones that can contribute to slowing your metabolism.
2. You feel sluggish and weak.
Your muscles store carbohydrates inside for fuel as something called glycogen—this fuel is used by your fast-twitch muscle fibers in high-performance situations like picking up something really heavy or sprinting. When you aren’t eating enough, your body can eat through your glycogen stores, which robs your muscle of this high-performance fuel.
Robbed of calories and forced into a “starvation mode,” your body will also start to eat away at muscle for energy rather than attacking your fat stores—that’s why people on extremely low-calorie diets often lose 30 percent of their weight as muscle, and why starvation dieters often look “skinny fat” rather than healthy and slim.
The compound effect is that you’ll feel tired and weak if you’re not eating enough. And don’t think you can just sleep it off: One side effect reported from extremely low-calorie diets is a difficulty falling and staying asleep, a symptom experts associate with uneven blood sugar levels.
3. You’re very, very “hangry.”
That feeling when you can’t control your emotions, snap at people, and feel irrationally angry because you’re so hungry? That’s being “hangry,” and science backs up its existence: When your blood sugar gets low, studies suggest that self-control is one of the first things to go. So you can’t control your emotions, and you snap—you might be losing weight, but you might also lose all your friends.
That loss of self-control also means a loss of impulse control—so when you’re hangry, you may also be susceptible to a big, caloric binge, which would undo all the supposed “good” you did while undereating.
The solution: Eat enough to maintain a balanced blood sugar level. If you’re getting “hangry,” you may be eating too little.
4. Your skin’s dry, flaky or itchy.
This one has to do with fat calories: The fatty oils in your diet not only make skin-helping Vitamins like A, D, and E more bio-available, but the fat itself can improve the health of your skin.
And multiple studies have shown that eating the right fats—“healthy” fats like those found in olive oil—can help your body lose weight, specifically around your belly. Dieters in Germany were given yogurt with olive oil added in as a supplement to their normal diet. Even though this yogurt was added as extra calories, the dieters did not gain weight or body fat—and they had more feelings of fullness than those who ate the yogurt without the oil.
5. You’re having abnormal diarrhea or constipation.
When your body slows down to conserve energy—because you’re not eating enough—your digestive system can also slow down. Your intestinal lining can become damaged or less effective in this case—meaning that the food you do eat doesn’t get digested correctly. Not only does this cause a deficiency in how many nutrients are absorbed by the body, but it can also cause diarrhea or constipation. And that just makes things worse: When you have diarrhea, your body is depleted of vitamins and minerals.
6. Your diet is just really hard to stick to.
When a weight loss plan is sustainable, it creates what you may have heard of as a “lifestyle change”: Successful dieters learn to make better choices that they can continue to make in the long run. It’s that feeling of “I can do this!” that keeps people on track, losing and, eventually, staying healthy.
When you’re not eating enough, though, the weight loss plan can feel like a diet—an impossible struggle of hunger, anger, pain and anguish. That’s a strategy that results in relapse, not lifestyle change. Add in the effects on your metabolism and exercise performance, and the extremely low-calorie diet isn’t even faster or more effective. Eat the right amount, and you may have an easier time staying on plan.