Trying to shed some weight? You may have heard of the 1200-calorie diet. Whether it’s because you need to or simply want to, the key to losing weight fast is to take in fewer calories than you burn. The challenge is figuring out exactly how many calories it takes in order to lose weight without driving yourself mad from hunger. Turns out, science has already done it for you: the 1200-calorie-per-day threshold seems to be the sweet spot, providing your body with enough fuel to get through the day while still helping you drop a few pounds.

What is the 1200-calorie diet?

“A 1200-calorie diet is a diet focused on counting calories; it is primarily for weight loss, as it is a low calorie meal plan. Losing weight this way emphasizes a calorie level, rather than types of foods or nutrients being consumed,” says Daniela Novotny, registered dietitian and instructor of biomedical sciences at Missouri State University.

The good news about following a 1200-calorie diet is that you don’t have to follow a strict list of foods you can and can’t eat. You can choose a plant-based diet or a clean-eating approach, you can go keto, or you can eat the foods you love but pare back portion sizes. You simply need to keep track of the calories you’re eating throughout the day and avoid going much higher than 1200. The best way to do that? Use one of the many calorie counting apps out there to keep track, like MyFitnessPal or Cron-o-meter.

That said, you’ll quickly find that your choices definitely affect your success when it comes to following a 1200-calorie diet. Ryan Maciel, RD and Head Nutrition Coach—Elite Athletes and Organizations for Precision Nutrition says, “since it’s such a restrictive diet, you do want to focus on consuming mainly whole foods, having well-balanced meals made up of lean protein, vegetables, healthy carbohydrates and healthy fats. This is really going to help keep you full for a longer period of time and give you a better chance of success.”

How to follow a 1200-calorie diet

While you may not need any gadgets or gizmos to follow the 1200-calorie diet, there’s one thing you definitely will need, and that’s a plan! For most people, limiting daily caloric intake down to 1200 is a pretty drastic cut. So in order to avoid mood swings and blood sugar imbalances, it’s a good idea to draw up a meal plan to follow, even if it’s just a rough idea of what you’ll eat as you follow the 1200-calorie diet.

The National Heart, Lung and Blood Institute has put forth a healthy guide with examples for all three meals, and includes small amounts of fats like margarine and mayonnaise to keep you feeling fuller. Their recommendations also include several glasses of water each day. Need more inspo? Pinterest is a great place to search for 1200-calorie diet ideas.

How much weight can you lose on the 1200-calorie diet?

If you want to lose weight fast, restricting your calories to 1200 is certainly an effective way to do it. But, how much weight can you lose on the 1200-calorie diet isn’t an exact science. “There’s a lot that goes into calculating someone’s energy needs for the day, like their height, age, weight, sex, how much they move throughout the day, how much physical activity they do,” says Maciel. “And then, of course, everybody’s metabolism is slightly different. But the average weight loss that most people see on the 1200 calorie diet is about one to two pounds per week.”

If you choose to follow the 1200-calorie diet, you may find you lose more weight in the first week, simply due to the large changes you’re making to your diet, especially if you’re opting for healthier food than you were before beginning the diet. After that, weight loss may begin to level off a bit.

Advantages of the 1200-calorie diet

The biggest, and some might argue the only, advantage of following the 1200 calorie diet is rapid weight loss. And since most adherents to this diet tend to stick to whole, unprocessed foods, a healthier lifestyle is a fringe benefit as well.

Drawbacks of the 1200-calorie diet

One of the biggest drawbacks of the 1200-calorie diet is the fact that it’s just not a fun plan to follow. No matter what foods you eat, or how you space them throughout the day, you’re bound to experience some amount of hunger on this diet. “Not all diets are going to have you reduce your calorie intake by this much, says Maciel. “Twelve hundred calories is really the low end. Anything lower than that and you run the risk of developing nutrient deficiencies.”

As such, the 1200 calorie diet can be exceptionally difficult to stick with for the long term. “Due to the fact it is not often maintainable, a 1200-calorie diet is often followed by a time where you tend to eat a larger amount of calories, leading to weight gain. True, lasting weight loss rarely occurs following extremely low calorie diets,” says Novotny.

Finally, constantly counting calories can lead to an unhealthy preoccupation with food, especially if you’ve dealt with an eating disorder in the past. A much better way to lose weight if you’ve ever struggled with disordered eating is to combine healthy food choices with daily exercise.

In conclusion, limiting yourself to only 1200 calories each day is an effective way to lose weight for the vast majority of people. And while this diet isn’t overly difficult to follow, it is challenging to stick with, since there are very few cheats or rewards to look forward to. The best way to do the 1200 calorie diet may be to follow it for a few weeks or months, then slowly add more calories without adding in a bunch of junk food like sweets or processed food.