Counting calories and creating a calorie deficit are some of the more successful tactics people use when trying to lose weight. But if you are considering drastically reducing your caloric intake to just 1,000 calories per day, you will probably be doing more harm than good. Although we’ve been trained to think of calories as “the enemy” thanks to toxic diet culture, calories are energy, and we need them to survive. In fact, the 2020-2025 Dietary Guidelines for Americans include an estimated calorie needs of 1,600 to 2,400 calories a day for females, and 2,000 to 3,000 calories a day for males. “These numbers, however, do not take into consideration your physical, medical, or emotional needs. Diets should be individualized, not a one-size-fits-all approach,” notes Bonnie Taub-Dix, RDN, creator of BetterThanDieting.com and author of Read It Before You Eat It: Taking You from Label to Table.

Is the 1,000 calorie a day diet safe?

A 2013 study suggested that prescribing 1,000 calorie diets versus 1,500 calorie diets is more likely to result in significant weight loss for obese individuals. While low-calorie diets may lead to weight loss, not eating enough calories can have a negative impact on the body, and if you are trying to eat just 1,000 calories per day, it is not safe, according to registered dietitian Jonathan Valdez, RDN, owner of Genki Nutrition and a spokesperson for the New York State Academy of Nutrition and Dietetics. And it can negatively affect you in the following ways:

Short-term risks of eating 1,000 calories a day may include dizziness, hunger, gallstones, nausea, fatigue, headaches, and nutrient deficiencies.It can lead to nutrient deficiencies, slow metabolism, and make bones weaker if you exercise along with a low-calorie diet.Eating too few calories can make it harder to meet your daily nutrient needs because you may be depriving yourself of certain foods and adequate amounts of vitamins and minerals.Cutting calories too drastically can lead to a slower metabolism, which can make it harder to lose weight and makes it more likely that you will regain it after you restart a normal diet.

For most people, a diet of 1,000 calories per day might is likely to backfire. “That initial weight loss might make it seem like your diet is ‘working’, but when you’re feeling deprived and the pounds are not pouring off, there’s a tendency to give up and go back to the habits that you were trying to escape in the first place,” adds Taub-Dix. “For example, if you ate just 1,000 calories worth of chocolate cake every day, you’ll probably lose weight, but you might also lose your hair, your teeth and your interest in the chocolate cake after awhile!” A real long-term risk is a weight regain with low-calorie diets, especially when your diet is as restrictive as this one: A 2015 long-term outcome study found that one-third of dieters may regain more weight than they originally lost.

The bottom line

a 1,000 calorie diet is likely to have more negative effects than positive ones, and is not recommended by registered dietitians. However, if you are looking to lose weight, they suggest working with a registered dietitian nutritionist who can help you create a meal plan to help you lose weight in a calorie deficit in a safe and healthy way. Next up: How Many Steps a Day Actually Leads to Weight Loss? 

Sources

Bonnie Taub-Dix, RDN, creator of BetterThanDieting.com and author of Read It Before You Eat It: Taking You from Label to TableJonathan Valdez, RDN, owner of Genki Nutrition and a spokesperson for the New York State Academy of Nutrition and Dietetics Is the 1 000 Calorie a Day Diet Safe  - 8