The 1000 Calorie Diet Guide: What To Expect

A 1000 calorie diet involves eating only 1000 calories a day. This can be thought of as an extreme or highly-restrictive diet and is generally not recommended for most people due to the fact that it is significantly below their daily energy needs.

However, a 1000 calorie diet plan can be appropriate for smaller people who have a lower BMR and aren’t particularly physically active or for obese or morbidly obese individuals (BMI over 30 kg/m2) under medical supervision.

In this article, we will discuss a 1000 calorie diet, including what a 1000 calorie meal plan looks like, and if 1000 calorie diet plans actually work.

We will cover: 

  • What Is a 1000 Calorie Diet?
  • Are 1000 Calorie Diets Safe?
  • Do 1000 Calorie Diet Plans Work?
  • What Can You Eat On a 1000 Calorie Diet Meal Plan?

Let’s get started!

A notebook with the word calories on it, and apple, measuring table and fork.

What Is a 1000 Calorie Diet?

A 1000 calorie diet plan involves eating 1000 calories a day.

Some people choose to follow a 1000 calorie meal plan every day in the week, or they may eat 1000 calories a day a few times per week or every other day, interspersed with higher calorie days with normal eating.

The latter approaches tend to be safer, healthier, and more sustainable for most dieters.

Are 1000 Calorie Diets Safe?

In general, habitually eating 1000 calories a day is not advisable or sufficient for most individuals. 

According to the National Health Service (NHS) in the UK, a “very low-calorie diet” provides about 800 calories or fewer, so although a 1000 calorie meal plan isn’t quite below this threshold, it is certainly a low-calorie diet and an insufficient energy intake for most people.

In general, very low-calorie diets with such severe restrictions are reserved for morbidly obese people who are planning to have weight loss surgery, preparing for fertility treatments, or managing diabetes. Such caloric restriction is rarely indicated for healthy individuals.

The NHS reports that very low calorie diets require medical supervision and should only be followed for a maximum of 12 weeks. 

A notebook with notes about BMR, a measuring tape, and cup of tea.

Do 1000 Calorie Diet Plans Work?

The effects of a 1000 calories diet will depend on your body size, activity level, how long you follow the diet, how often you eat 1000 calories a day (every day or periodically), and the quality of your 1000 calorie diet plan.

In general, you can expect initial weight loss when following a 1000 calorie diet because most people need significantly more calories per day.

According to the NHS, the recommended calorie intake for women is 2,000 calories a day and 2,500 calories per day for men. Your caloric needs will be higher if you are larger or physically active. 

Therefore, eating 1000 calories per day represents a caloric deficit of 1000-1500 calories per day for most people, depending on sex.

You can estimate your BMR with online calculators such as the one here. Learn more about calculating your TDEE here.

You can also estimate your caloric needs here.

Someone using a tablet and calculating calories.

Although the Centers for Disease Control and Prevention (CDC) does recommend creating a caloric deficit to lose weight, a deficit of no more than 3,500-7,000 calories per week—which would yield 1-2 pounds of fat loss—is the suggestion for effective and sustainable weight loss. 

Therefore, eating 1000 calories per day every day could be workable for smaller individuals, but men or those with higher caloric needs may need to alternate eating 1000 calories a day with a higher caloric intake. 

Additionally, the suggestion is to generate this caloric deficit through a combination of dietary limitations and daily physical activity.

Some studies suggest that crash dieting can do more harm than good, especially from a psychological perspective. 

Furthermore, there’s a lot of evidence to suggest that many extreme diets that are not well-balanced and don’t include enough calories lead to rebound weight gain. In this way, although you may initially lose weight on a 1000 calorie diet, once you return to your normal way of eating, you will regain the weight that you lost.

Ultimately, this can lead to the phenomenon termed “yo-yo dieting,“ in which a dieter cycles between losing and regaining weight as they start and stop different diets.

This is thought to occur due to a survival mechanism known as adaptive thermogenesis.

Essentially, our bodies are capable of implementing metabolic adaptations when food is scarce, and energy intake is not meeting energy output.

Post-it notes that say BMR and DIET.

Adaptive thermogenesis helps your body conserve calories to minimize weight loss, which was necessary in primitive times when food could be scarce. 

Although eating 1000 calories a day in modern times is usually a deliberate decision to help lose weight, when prolonged or frequent, it can cause the same biological protective mechanisms to decrease metabolic rate and become more efficient at utilizing the limited number of calories coming in.

As a result, your basal metabolic rate (BMR) can drop, and your body simultaneously becomes adept at conserving calories by reducing energy expenditure in numerous ways

For example, there can be an increase in the secretion of fat-storing hormones such as insulin and peptide YY, a decrease in body temperature and the rate of digestion, and hormonal changes that can increase hunger and decrease the feeling of satiety to encourage you to eat more. 

Finally, energy levels decrease, reducing the desire to exercise and be active throughout the day, and reducing the potential intensity of those activity levels.

Therefore, if you are going to follow a 1000 calorie diet, it is usually best to do so in a cyclic pattern, much like carb cycling or alternate day intermittent fasting, in which some days you eat 1000 calories a day, and other days in the week you eat the number of calories your body actually needs.

This may help “trick” your body into thinking food is not scarce so that the adaptive thermogenesis response does not kick in.

A large variety of fruits and vegetables.

What Can You Eat On a 1000 Calorie Diet Meal Plan?

A 1000 calorie diet meal plan doesn’t necessarily have foods that are banned, but because the daily calorie limit is so low, focusing on volumetrics with your eating, which means trying to eat nutritionally-dense but not calorically-dense foods, is the best way to feel satiated on so few calories.

This involves eating lower-calorie foods that still fill you up, such as foods high in fiber and water, and minimizing calorically-dense foods such as fats, oils, processed foods, refined grains, packaged snacks, and sweets, as these foods won’t be as filling and provide very little nutritional value.

Here are good foods to eat on a 1000 calorie meal plan:

  • Vegetables: Spinach, kale, Swiss chard, bok choy, broccoli, zucchini, carrots, artichokes, leeks, cucumbers, onions, cauliflower, asparagus, radishes, etc.
  • Low-Sugar Fruits: Pears, melons, oranges, apricots, berries, lemons, kiwis, tomatoes, etc.
  • Fish and Seafood: Salmon, trout, cod, haddock, flounder, sardines, tuna, mackerel, lobster, crab, scallops, shrimp, mussels, clams, squid, etc.
  • Poultry: Chicken, turkey, duck, quail, etc. Lean cuts are best.
  • Egg whites and eggs
  • Low-Fat Dairy: Cottage cheese, skim milk, Greek yogurt, etc.
  • Unsweetened Beverages: Tea, coffee, water, club soda, etc.
  • Lean Meats: Bison, lean pork, lean beef, etc.
  • Legumes, whole grains, and starchy vegetables in moderation
A variety of mini desserts on a platter.

Foods to avoid due to either high caloric content or low nutrient density include the following: 

  • Nuts and Seeds: Almonds, pistachios, walnuts, cashews, pecans, chia seeds, flax seeds, peanut butter, peanuts, pumpkin seeds, tahini, nut butter, sesame seeds, hemp seeds, sunflower seeds, macadamia nuts, Brazil nuts, etc.
  • Fats and Oils: Cream, butter, ghee, olive oil, avocados, flaxseed oil, coconut oil, coconut, margarine, etc.
  • Full-Fat Dairy: Cream, whole milk, reduced-fat milk, ice cream, buttermilk, fatty cheeses, etc.
  • Fatty meats
  • Processed grains
  • Desserts and Sweets: Ice cream, pastries, cookies, doughnuts, pies, pudding, sweetened yogurt, etc.
  • Dried Fruit: Dried apricots, raisins, dried dates, prunes, etc.
  • Sweeteners: Sugar, honey, agave, high-fructose, corn syrup, jellies, jams, pudding, fruit juices, soda, sweet tea, applesauce, etc.

With your 1000 calorie meal plan, try to space out your meals and divide your calories throughout the day with roughly a 250-calorie breakfast, 350-calorie lunch, and 400-calorie dinner. Drink plenty of water.

When you are eating so few calories per day, food quality really matters. Make sure you are eating a balanced diet and taking the supplements necessary to prevent deficiencies. 

Work with your doctor or a registered dietician to devise a healthy 1000 calorie meal plan or healthier alternative diet that better meets your needs.

If you have thought about intermittent fasting as a weight loss tool, check out our guides here.

A notebook that says intermittent fasting a clock and a plate.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, and contributes to several fitness, health, and running websites and publications. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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