Nutrition / Food

Why Calorie Deficit Diets May Not Work

Calorie cutting is not a one-size-fits-all approach.

The widely held belief about calories and weight loss is simple: If you want to lose weight, you need to cut back on your caloric intake. Gaining weight, on the other hand, happens when you eat more calories than your body uses. However, the reality is less straightforward. Calories are not created equal, and bodies are all different, too. This means that a calorie-deficit diet is not necessarily the right—or healthiest—weight-loss solution.

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“More important than simply cutting [calories] would be eating differently,” says Registered Dietitian Olivia Cupido. “Somehow the number ‘1200 calories’ got into mainstream media as a goal number, but that is quite low and certainly not for everyone.”

Why cutting calories isn’t for everyone

Adults need an estimate of anywhere between 1,600 to 2,400 calories per day for women and  2,000 to 3,000 for men, according to the Office of Disease Prevention and Health Promotion’s latest dietary guidelines. Caloric needs vary on factors like age, weight, sex, height, and physical activity level.

Cupido says that for people looking to lose weight, it’s best to think about ways to make healthier choices rather than decide to simply cut calories or eliminate foods. Certain calorie-dense foods like salmon and avocado, for example, are high in nutritional benefits like Omega-3 fatty acids. Foods that are high in calories, yet offer little to no nutritional benefit, on the other hand, can be swapped out for more nutritious stuff. Even trading sugary drinks like soda—which is often high in calories—for water can make a big difference.

“Are there empty calories that aren’t serving you? Can we time out meals better? Can we incorporate exercise and activity?” Cupido asks. “I think people should consider these things before simply cutting back.”

Take two breakfast options for example: a croissant may have 400 calories, while two eggs and half an avocado may have around 280. The eggs and avocado meal not only has fewer calories, but it also has health benefits like fiber, Omega-3s, protein, and potassium. Not only will filling up on nutrient-rich foods keep you full longer, but it will also promote a healthier weight for your body.

How many calories are safe to cut out?

It’s hard to give an exact amount of calories that is safe to cut out of a diet, Cupido says, because everyone’s needs are different. What’s important is not cutting back on any macronutrients, including carbs, fats, and proteins. Maintaining an active lifestyle is vital, too, and exercise requires the proper fuel.

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“Slight calorie restrictions can be safe, as long as you are getting the essential nutrients you need,” Cupido says. “It does depend on the person, but I would say somewhere around the 500 calorie mark, or about a 25 percent decrease, is safe.” (Again it’s important to note that this amount is not for everyone, and it’s best to check with your health care provider if you’re unsure.)

Just like with exercise, it’s best to be realistic about weight-loss goals. If you want to develop healthier eating habits and a more balanced approach to food, it requires a lifestyle change—and that’s not something that happens overnight. If you beat yourself up over every single food choice, or get upset when you’re not seeing the progress you hoped for, it can be detrimental to your well-being.

“I see too many people starving themselves, stressed out, unhappy, and not eating or doing anything they enjoy,” Cupido says. “[It’s] important to be realistic about expectations and goals.” Instead, Cupido says that it’s best to adopt a healthy and balanced approach to diet and exercise. Aim to get all the nutrients you need, and practice mindful or intuitive eating. That way, you’re making healthier choices that will benefit you in the long-run—not just for a certain period of time.

What happens when you eat too few calories?

Let’s be clear: Eating fewer calories than your body needs is not a good idea. A diet that is too low in calories can slow the metabolism and, in turn, affect health and weight-loss. Plus, if you’re not getting the nutrients your body needs, you could be putting yourself at risk for vitamin deficiencies.

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Cupido says that eliminating all carbs isn’t a great idea either. Cutting carbs can result in a diet that’s too low in fiber, which can cause constipation. Likewise, don’t say goodbye to all calcium-rich foods. “You don’t want to be putting your bones at risk, so definitely leave room for calcium-rich sources,” she explains.

Becoming too consumed with counting calories and restricting food intake can also lead to disordered eating habits or an eating disorder. When food is seen as “good” or “bad,” it has a lot of control over us—which can cause great stress in our lives.

“The more rules and restrictions we give ourselves on our diets, the more opportunities we have to break them, feel stuck, and get upset with ourselves,” Cupido says. “This never ends well, and disordered eating can be a slippery slope—especially for those with [a] genetic predisposition to eating disorders, which comes with a whole host of additional physical risks.”

Lastly, extreme calorie restriction has been linked to depression, irritability, and fatigue, Cupido says. It can also lead to muscle wasting, low iron, and irregular periods for women.

The Bottom Line

It’s important to maintain a healthy lifestyle complete with a balanced diet and regular exercise routine (try Aaptiv!), but obsessing over calories isn’t great for our well-being. If you want to lose weight or cut calories think about making healthier food choices first, and swapping out less-nutritional items for more nutritious ones. Because, at the end of the day, our body needs calories to run, and it’s important we fuel it the best way possible.

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