A 1,000 calorie diet plan is an eating strategy that drastically cuts the number of calories a person consumes each day. People may turn to 1,000 calorie diets when they are desperate to lose weight quickly, such as before a vacation. While adults could follow this type of diet relatively safely for a couple of weeks, it is not something that doctors advise for extended periods. However, drastically cutting calories does not typically result in sustained weight loss and may be harmful. Extreme diets have undesirable effects and do not result in sustained weight loss. Instead, it is better to reach a moderate weight gradually with a balanced diet that a person can follow long term.
This article discusses 1,000 calorie diets, their safety, and their effectiveness. It also includes some tips for safe weight loss.
Understanding the Basics of a 1,000 Calorie Diet
A 1,000 calorie diet plan is an eating strategy that drastically cuts the number of calories an individual consumes each day. Experts consider this type of diet dangerous because they provide significantly fewer calories than the average adult needs for health and well-being.
The term calorie describes the amount of energy in foods or drinks. The human body requires this energy to fuel essential metabolic processes. The number of calories an individual needs each day varies based on biological sex, height, weight, activity level, and genetics. According to the Dietary Guidelines for Americans 2020-2025, the average female adult needs about 1,800-2,400 calories daily, while the average male adult needs about 2,400-3,200 calories.
Being in calorie deficit aids weight loss. A calorie deficit means using up more calories than you intake. However, research has not identified the optimal deficit, and it likely depends on the individual. Although some diet plans may recommend consuming 1,000 calories a day or less as an effective tool for weight loss, it is not safe and is an unsustainable way to try and lose weight.
Read also: Healthy Vegetarian Eating
The Risks and Downsides of Extreme Calorie Restriction
Dieting can have harmful outcomes and typically has more risks than benefits. Research associates dieting with long-term weight gain and the possibility of developing eating disorders. When a person has an eating disorder, their eating habits can damage their physical health and ability to live a regular life. Studies also show that the prolonged semi-starvation caused by continuous dieting can lead to severe depression, emotional distress, and irritability. Once individuals return to a non-dieting state, they may experience a loss of control over their eating habits and develop a strong desire to eat more.
Extreme reductions in calorie intake can cause harmful side effects, such as:
- Dizziness
- Extreme hunger
- Gallstones
- Nausea
- Fatigue
- Headaches
- Nutrient deficiencies
These diets can also change specific metabolic pathways inside the body. For example, they can change hormones such as ghrelin and cortisol, which play a role in feelings of hunger. They can also decrease muscle mass and affect the number of calories the body uses each day. This increases the risk for weight regain once an individual no longer maintains the diet.
The (Unsustainable) Promise of Weight Loss
Some evidence shows that these diets can promote weight loss. An older study of 125 females with obesity involved the participants consuming either 1,000 calories or 1,500 calories daily for a year. The people assigned to the 1,000 calorie diet lost more weight than the 1,500 calorie group. What’s more, the 1,000 calorie group experienced more weight regain than the 1,500 calorie group.
Other studies also sustain that while consuming 1,000 calories a day may result in significant weight loss, most people cannot sustain it and often experience significant weight regain. The reasons include regaining lost muscle mass and increased appetite.
Read also: Diet Before Bariatric Surgery
Also worth noting is that the human body can adapt. Significantly decreasing caloric intake causes the body to decrease the energy it burns. Typically, when individuals increase their calorie intake, they regain the lost weight. They may even gain more weight because they are in a caloric surplus, which means they eat more calories than their body needs to function.
A Safer Approach: Gradual Changes and Healthy Habits
People who want to reduce calories to lose weight should do so in small increments and avoid drastic changes. The best way to lose weight safely and successfully is by adopting healthy eating habits.
Start with small, realistic goals, and then, as these become a habit, increase the goals. For example, make it a goal to start each dinner with a side salad or serve vegetables as a side dish. Once this becomes standard practice, introduce a second goal, such as having fruit with breakfast.
Also, think about setting some exercise goals. A good example is setting a goal to walk for 15 minutes 3 times a week. Once this becomes routine, increase the time or number of sessions each week.
Setting small goals and increasing them over time sets people up for success. Also, small goals are easy to implement and sustain.
Read also: Complete Guide to 1500 Calorie Vegan Meals
Remember that it takes time to gain weight, so it may take even more time to lose weight safely. Quick weight-loss plans have little scientific support and can lead to individuals regaining all the weight they lost and more.
The Role of Protein in Weight Loss
Protein is one of the three macronutrients, along with carbs and fat. It plays a key role in the formation, maintenance, and structure of your organs and tissues.
Protein is made up of a chain that contains 20 smaller units called amino acids. Of these, nine are considered essential amino acids. They must be consumed in food because your body can’t make them.
Increasing your protein intake may help promote weight loss in many different ways.
- Appetite and fullness: Protein increases the production of hormones like PYY and GLP-1, both of which help you feel full and satisfied. A 2020 review also found that protein reduces levels of ghrelin, known as the “hunger hormone.” These effects of a high protein intake could lead to a natural reduction in food intake.
- Metabolic rate: A 2018 review found that higher protein intake may boost your basal (BMR) and resting (RMM) metabolic rates. This can help you burn more calories for several hours after eating, as well as during your sleep. Protein may also increase how much energy your body uses to absorb, metabolize, and store food. This is called the thermic effect of food (TEF). The TEF for protein is 20-30%, meaning that 20-30% of the calories found in protein are used simply to digest it. Meanwhile, the TEF for carbs and fat is 5-10% and 0-3%, respectively.
- Body composition: Protein’s ability to suppress appetite, promote fullness, and increase your metabolism can help you lose weight. A 2020 review found that increasing protein intake promotes weight and fat loss while retaining muscle mass. The authors also note that high protein intake has long-term weight loss benefits and could help prevent weight regain. Typically, when you reduce your calorie intake, your metabolism slows down. This is partly due to muscle loss. However, a higher protein intake can help protect against muscle loss and keep your metabolic rate up.
In addition to its effects on weight management, protein may also help:
- Increase muscle mass
- Reduce muscle loss during aging
- Reduce bone loss
- Improve wound healing
How Much Protein Is Enough?
The Recommended Dietary Allowance (RDA) of protein is 0.8 g per kilogram of body weight (g/kg/bw), or 0.36 g per pound of body weight (g/lbs/bw). However, the authors of a 2019 review suggest that this number is often misinterpreted as the ideal number. It’s only the minimum amount of protein required to prevent nutrient deficiencies and muscle loss in most healthy individuals. Research suggests that eating more protein than the RDA may promote weight loss and overall health. For example:
- A 2017 study found that participants who ate a high protein diet of 1.34 g/kg/bw (0.6 g/lbs/bw) for more than 75% of the 6-month duration experienced significantly more weight loss than the group who followed the RDA requirements.
- A 2016 review found that eating up to 2 g/kg/bw (0.9 g/lbs/bw) may help promote strength and prevent muscle degeneration.
- A 2015 study found that females ages 65 years and older require 1.3 g/kg/bw (0.6 g/lbs/bw) of protein to help prevent age-related muscle loss.
- A 2015 review found that eating up to 1.6 g/kg/bw (0.7 g/lbs/bw) per day can help promote weight loss, reduce body fat, and maintain muscle mass.
Consuming protein beyond 2 g/kg/bw (0.9 g/lbs/bw) may not provide additional benefits. A 2013 study found that participants who consumed 1.6 g/kg/bw (0.7 g/lbs/bw) lost slightly more fat and had similar gains in muscle compared to the group that consumed 2.4 g/kg/bw (1.1 g/lbs/bw).
So, if you weigh 68 kg (150 lbs), this provides 82-136 g of protein daily.
Speak with a healthcare professional or registered dietician if you want to lose weight and are unsure about how many calories and grams of protein you should be eating. They can develop a nutrition plan that’s right for you.
Sample High Protein Meal Plan (Around 100g Protein/Day)
Here’s a sample menu that provides about 100 g of protein per day. You can adjust the portions to meet your needs.
Monday
- Breakfast: 3 eggs, 1 slice whole grain toast with 1 tablespoon almond butter, and 1 pear.
- Lunch: Fresh avocado and cottage cheese salad and an orange.
- Dinner: 6 ounces (oz) (170 g) steak, sweet potato and grilled zucchini.
Tuesday
- Breakfast: Smoothie made with 1 scoop protein powder, 1 cup coconut milk, and strawberries.
- Lunch: 4 oz (114 g) canned salmon, mixed greens, olive oil and vinegar, and an apple.
- Dinner: 4 oz (114 g) grilled chicken with quinoa and Brussels sprouts.
Wednesday
- Breakfast: Oatmeal and 1 cup plain Greek yogurt with 1/4 cup chopped pecans.
- Lunch: 4 oz (114 g) chicken mixed with 1 avocado, red bell pepper, and peach.
- Dinner: Turkey pumpkin chili and brown rice.
Thursday
- Breakfast: Omelet made with 3 eggs, 1 oz cheese, chili peppers, black olives and salsa, and an orange.
- Lunch: Leftover turkey pumpkin chili and brown rice.
- Dinner: 4 oz (114 g) halibut, lentils, and broccoli.
Friday
- Breakfast: 1 cup cottage cheese with 1/4 cup chopped walnuts, diced apples, and cinnamon.
- Lunch: 4 oz (114 g) canned salmon mixed with healthy mayo on sprouted grain bread, and carrot sticks.
- Dinner: Chicken meatballs with marinara sauce, spaghetti squash, and raspberries.
Saturday
- Breakfast: Frittata made with 3 eggs, 1 oz cheese, and 1/2 cup diced potatoes.
- Lunch: Leftover chicken meatballs with marinara sauce and spaghetti squash with an apple.
- Dinner: Fajitas with 3 oz (85 g) shrimp, grilled onions, bell peppers, guacamole, and 1/2 cup black beans on a corn tortilla.
Sunday
- Breakfast: Protein pumpkin pancakes topped with 1/4 cup chopped pecans.
- Lunch: 1 cup plain Greek yogurt mixed with 1/4 cup chopped mixed nuts and pineapple.
- Dinner: 6 oz (170 g) grilled salmon, with potatoes and sautéed spinach.
Some high protein snacks can also help you boost your protein intake and promote weight loss.
Risks Associated with High Protein Diets
High protein diets are generally safe and healthy for most people. For example, a 2019 review found that contrary to popular belief, high protein intake above the RDA doesn’t cause kidney problems in people with normal kidney function. That said, you may need to eat a low protein diet to preserve kidney function if you’ve received a diagnosis of moderate to advanced kidney disease. A 2022 review also found that nondairy animal protein, total meat and meat products, and processed meat were linked with a higher risk of kidney stones. However, dairy protein was associated with a lower risk of kidney stones. Speak with a healthcare professional or registered dietitian about how much protein you should consume each day if you have kidney disease.
Food Choices for a High Protein Diet
It’s important to consider a wide range of protein sources. This may include animal and plant-based foods, including:
- Soy
- Eggs
- Dairy
- Meat
- Fish
- Poultry
- Beans
- Legumes
- Grains
- Nuts
Eating high protein foods could help you lose weight because protein may keep you satiated for longer and boost your metabolism.
Sample 1000 Calorie High Protein Meal Plan
Here's a sample High Protein meal plan with daily averages of 992 Calories, 77g protein, 45g fat, and 78g carbs (57g net carbs).
Day 1
- Breakfast
- Lunch
- Dinner
- Snack
Day 2
- Breakfast
- Lunch
- Dinner
- Snack
Day 3
- Breakfast
- Lunch
- Dinner
- Snack
Day 4
- Breakfast
- Lunch
- Dinner
- Snack
Day 5
- Breakfast
- Lunch
- Dinner
- Snack
Day 6
- Breakfast
- Lunch
- Dinner
- Snack
Day 7
- Breakfast
- Lunch
- Dinner
- Snack
Other Types of 1000 Calorie Diet Plans
- Keto: Low-carb, high-fat diet focusing on ketosis for energy and weight management
- Vegan: Excludes all animal products, emphasizing plant-based foods for health and ethics
- Vegetarian: Plant-based diet including dairy and eggs, avoiding meat for health and ethics
- Paleo: Emulates ancient diet with whole foods, free of processed items and grains
- Mediterranean: Rich in fruits, vegetables, fish, and olive oil for a balanced, heart-healthy diet
- Low Carb: Reduces carbohydrate intake, focusing on proteins and fats for energy
- Low Fat: Limits fat consumption, emphasizing lean proteins, grains, and vegetables
- High Protein: Prioritizes protein intake for muscle growth and repair, with balanced nutrients
- Gluten Free: Avoids gluten, suitable for celiac or gluten sensitivity, focusing on alternative grains