What Is a Low-Calorie Diet?

A low-calorie diet is a structured eating plan that restricts daily caloric intake, commonly for weight loss. Following a low-calorie diet typically means consuming around 1,200 to 1,500 calories per day, which creates a calorie deficit that can lead to weight loss. A low-calorie diet can be effective, but it requires a lot of discipline to work and be safe. Ideally, you should seek help from a registered dietitian or doctor to not overly restrict your calories or miss out on essential nutrients.

Scientists have been studying low-calorie diets since as far back as the 1980s, investigating claims that these restrictive eating plans may slow the aging process. But for weight loss, the science is simple: Take in fewer calories than you burn (via daily living and deliberate exercise), and you will lose weight.

However, just because the science is simple does not mean actually following a low-calorie diet plan is easy. It takes planning and effort to understand and recognize hunger cues and make sure those 1,200 to 1,500 calories are enough to fuel the body and contain the right nutrients.

That's why a low-calorie diet is not recommended for everyone, including pregnant or breastfeeding women (who need enough calories to sustain their growing babies as well as themselves) and athletes (who need the energy from sufficient calories to perform).

What Can You Eat?

While there isn't one official low-calorie diet, nutrition experts say that you'll want to choose healthy, whole foods that are naturally low in calories for a sustainable eating plan. You have the freedom to consume your calories whenever it works for you, but you may find that it's easier to stick with a low-calorie plan when you spread your intake over the course of a day.

Low-calorie diets require counting calories. To count calories, you'll need to know how much food you're eating at each meal. Proponents of low-calorie diets often recommend starting with a kitchen scale and measuring cups to measure out all your servings, at least until you feel comfortable estimating your portions visually. Remember that your beverages may contain calories, so you need to measure and count what you drink.

You'll increase your chances of success if you keep track of all the foods you eat. Keep your food diary in a notebook or with a calorie counter app such as MyFitnessPal or one included with a fitness monitor such as Fitbit. Food trackers keep a daily log of your calories and also grade your diet for nutritional value. A food diary allows you to realize any habits that could be interfering with weight loss, such as using food for comfort or as a reward.

What You Need to Know

Before you start a low-calorie diet, it's always a good idea to get a physical examination, especially if you have any health conditions such as high blood pressure or high cholesterol. It is also important to acknowledge (and get help for) any history of disordered eating. Issues can be explored and addressed with a registered dietitian or qualified therapist.

It's also recommended that you measure your body composition and decide on your goals. For example, you can record your waist circumference, and use that as a measure other than weight that can show your progress.

Next, determine your daily calorie need. This step is going to be different for everyone and will even change for you over time. One approach determines how many calories you need each day to maintain your current weight, then reducing that number by 100 to 500 calories.

It's OK to start slowly with just a small reduction in calories. After all, low-calorie diets should be approached as a lifestyle modification—not a quick fix. If you're over-exuberant in the beginning, you might find the calorie restriction too difficult later on.

Since low-calorie diets call for reducing your overall caloric intake, every calorie must count toward your health goals, which can be accomplished by choosing nutrient-dense foods. Foods with plenty of fiber also help you feel full.

Fruits and Vegetables

Most fruits and vegetables give you a lot of bang for your calorie buck by offering fewer calories and more nutrients and fiber.

Lean Proteins and Low-Fat Dairy

Lean protein sources (such as grilled chicken or fish and low-fat dairy products) eliminate extra calories from fat while still giving you the protein your body needs.

Whole Grains

Healthy carbohydrates are not the enemy—your body needs them to function optimally. Choosing whole grains over refined carbohydrates gives you more nutrients and fiber along with your calories.

Herbs and Spices

Use them to add flavor to your food without adding calories. (Watch your sodium intake.)

Refined Carbohydrates

No foods are completely off-limits in a balanced low-calorie diet. But if you use up your daily calorie allotment on simple carbs, you risk missing out on important nutrients—and feeling hungry again quickly.

High-Fat Foods and Sweetened Beverages

While dietary fat is an important nutrient, consuming a lot of oil, butter, sugar, cheese, and fatty cuts of meat is another way to use up your daily caloric intake in a snap. The same goes for sweetened beverages, which can add up to a lot of calories very quickly. It's OK to use artificial or non-nutritive sweeteners sparingly to reduce your caloric intake; however, nutrition experts recommend focusing on nutritious low-calorie whole foods rather than sugar-free "junk" or processed foods.

Still, you may want to allow yourself 100 to 150 calories each day for a piece of candy, a few chips, or another favorite treat. Just be sure to watch your portions, so you don't inadvertently eat too much. The 2020-2025 Dietary Guidelines for Americans recommend keeping sugar intake to less than 10% of daily calorie intake, while the American Heart Association recommends no more than 100 calories a day (6 teaspoons) for most women and no more than 150 calories a day (9 teaspoons) for most men.

Pros and Cons

While there are many benefits to trying a low-calorie diet for weight loss, these eating plans have their drawbacks and may not be suitable for everyone. Review the pros and cons to inform your decision about whether a low-calorie diet plan is the right choice for you.

Accessibility

A low-calorie diet does not rely on specialty foods or dietary supplements. It simply calls for real, whole foods available at any supermarket (although you may want to look for low-calorie and low-fat versions of some foods, such as dairy products).

Effectiveness

If followed carefully, this diet is generally effective, especially in the short term. Research shows this type of diet can help overweight people lose weight. Long-term maintenance will require a lower-calorie diet than before the weight loss. When your weight goes down, your calorie requirement decreases, and you need to adjust your caloric intake accordingly. Remember, the goal of a low-calorie diet should be good health.

For long-term success, however, this diet requires lifestyle changes and added exercise. After you lose weight, your body requires fewer calories, so you can't go back to eating the way you did before starting the diet.

Safety

Low-calorie diets are generally safe if followed carefully and, ideally, recommended by and with a medical professional's guidance. A doctor or registered dietician can help you make sure you are getting the right mix of nutrients and enough calories to keep you safe and healthy.

Hunger

When you consume fewer calories than you are used to, you are likely to feel hungry at first—especially if your low-calorie meals lack protein and fiber. One of the primary challenges of low-calorie diets is managing appetite and keeping nutrition balanced by choosing nutrient-dense foods that are satisfying and within your daily calorie limit.

A low-calorie diet can backfire if you can only stick to it for a short time and then rebound with weight gain. It can help if you eat slowly and chew your foods thoroughly, enjoying each mouthful. Also, drink plenty of water. Your body needs fluids, and water contains no calories. Add lemon or lime slices for a bit of flavor.

To avoid hunger, aim to include high-fiber foods at every meal. Eat multiple servings of non-starchy vegetables at most meals and choose high-fiber carbohydrates such as whole grains and starchy vegetables like sweet potatoes. The 2020-2025 Dietary Guidelines for Americans recommend consuming 14 grams of fiber for every 1,000 calories you eat.

Practicality

Following a low-calorie diet recommended by a medical professional means a good deal of planning and careful tracking of the calories you consume. Unlike a very low-calorie diet (in which you only consume meal replacements), on a low-calorie diet, you make the decisions. You are in charge of your own food intake—what, when, and how much. While this freedom can be empowering, it can also be more challenging.

Not for Everyone

For some people, a low-calorie diet is not advised. That's why it's a good idea to check with your doctor before starting this or any weight-loss plan.

Is a Low-Calorie Diet a Healthy Choice for You?

The 2020–2025 Dietary Guidelines for Americans suggests a diet of 1,600 to 2,400 calories per day for most adult females and 2,200 to 3,000 for males for weight maintenance. To lose weight gradually at a healthy rate of 1 to 2 pounds per week, try using the U.S. Department of Agriculture's MyPlate plan to calculate your calorie needs to support weight loss.

A low-calorie diet would reduce daily calories to 1,200 to 1,800 for most adults, which may be too restrictive for some people, depending on their current health and health history. When followed with nutrition in mind, a low-calorie diet should offer balanced nutritional intake per USDA dietary guidelines.

Since calorie needs can vary greatly, determine yours (including how many you should consume a day to reach a weight loss goal) with this calculator.

Health Benefits

While proponents of low-calorie diets claim that it will lead to increased weight loss, research shows that maintaining an optimal intake of vitamins and minerals during severe calorie restriction is not feasible for most people. A diet that's highly restrictive is not sustainable or practical and could lead to unhealthy eating habits, which is why developing a low-calorie plan with the help of a medical professional is ideal.

Health Risks

If developed with balanced nutrition in mind and followed correctly, there are no common health risks associated with a low-calorie diet. However, following a low-calorie diet that focuses on an eating schedule is the opposite of mindful or intuitive eating, which is often an effective strategy for health, weight loss, and weight maintenance.

Additionally, not listening to your internal hunger cues can be problematic for those who have had an eating disorder or are at risk for developing one due to factors such as body image issues.

A Word From Verywell

"Low-calorie diet" is a broad term that encompasses many types of eating plans and a broad range of suggested intakes for calories. Consuming fewer calories than you burn is an effective way to lose weight, but following a low-calorie diet is not necessarily simple or easy. Do your research ahead of time and speak to a doctor or nutritionist to help you get started. This will boost your chances of weight loss success in a safe manner.

Remember, following a long-term or short-term diet may not be necessary for you, and many diets out there don’t work, especially long-term. While we do not endorse fad diet trends or unsustainable weight loss methods, we present the facts so you can make an informed decision that works best for your nutritional needs, genetic blueprint, budget, and goals.

If your goal is weight loss, remember that losing weight isn’t necessarily the same as being your healthiest self, and there are many other ways to pursue health. Exercise, sleep, and other lifestyle factors also play a major role in your overall health. The best diet is always the one that is balanced and fits your lifestyle.