1000 Calorie Deficit: How much weight can you lose?

A 1000 calorie deficit means you’re burning 1000 calories more than you’re consuming in a day. To achieve a 1000-calorie deficit for weight loss, you typically need to create a 7-day meal plan, reduce calorie intake in your diet, increase calorie expenditure through strength and aerobic exercise, or a combination of these approaches.

For example, you can achieve a 1000-calorie deficit in various ways: skip two meals per day, opt for snacks instead of full meals, reduce 500 calories from two meals, or burn an extra 500 calories through a one-hour jog.

Maintaining a 1000-calorie deficit a day could lead to losing around 2 pounds a week, given that a pound of body fat is roughly equal to 3,500 calories. However, keep in mind that metabolic adaptations might slow down your weight loss over time. In terms of safety, a 1000-calorie deficit isn’t universally recommended and can be tough on the body.

When aiming for a 1000-calorie deficit to create an energy imbalance for weight loss, various factors can contribute to the situation where weight isn’t decreasing despite maintaining such a deficit. These factors may encompass metabolic adaptations, underestimating calorie intake, or hormonal imbalances. In such a scenario, opting for a 1000-calorie deficit diet alternative, like a 500-calorie deficit, is a more sustainable, safe, and achievable approach.

1000 calorie deficit

What is a 1000 calorie deficit?

A 1000-calorie deficit occurs when you burn 1000 more calories in a day than you consume. The purpose of the 1000-calorie deficit diet is not just weight loss; it also aims to improve energy levels, mood, sleep, cardiometabolic health, and digestion. The definition of a 1000-calorie deficit varies among individuals because, unlike a 1000-calorie diet, it’s based on your Total Daily Energy Expenditure (TDEE).

To determine your calorie intake for a 1000-calorie diet, consider that the total daily energy expenditure for nonobese adults averages around 2443 ± 397 kcal/day, as revealed in the 2014 study titled “Energy requirements in nonobese men and women: results from CALERIE,” led by Leanne M. Redman and published in the American Journal of Clinical Nutrition. Consequently, aiming for a 1000-calorie deficit means you should aim to consume approximately 1,100 to 1,700 calories daily on average.

What is a 1000 calorie deficit for women?

On average, a 1000-calorie deficit for women equates to consuming 700 to 1000 calories per day, assuming that women, on average, have a 20% lower Total Daily Energy Expenditure (TDEE) of 580 kcal/day compared to men, as suggested by Dr. Redman. In this scenario, creating a 1000-calorie deficit is very similar to low and very low-calorie diets. Conversely, a 1000-calorie deficit for men is about 20% higher.

The average woman’s TDEE is 1863 kcal/day

What does a 1000 calorie deficit do to your body?

Creating a 1000-calorie deficit shifts your body from using glucose to burning fatty acids, potentially resulting in weight loss of up to 2 pounds per week or even more. However, it’s essential to understand that this approach isn’t a one-size-fits-all solution. According to a 2021 study conducted by Ju Young Kim at Seoul National University Bundang Hospital, while a calorie deficit is crucial for weight loss, it should be tailored to individual needs to prevent negative metabolic adaptations.

While some individuals can successfully maintain a 1000-calorie deficit diet, others may encounter heightened stress, and cravings, and eventually reach a weight loss plateau as a result of metabolic adaptations.

Sustaining a 1000-calorie deficit diet over the long term can result in hormonal changes, such as alterations in leptin, ghrelin, and insulin levels, along with a decrease in energy expenditure, known as adaptive thermogenesis. According to nutritionist and health consultant Mario García Martínez-Gómez, the more you stick to this deficit, the more your body adapts, making it progressively harder to achieve further weight loss. The following video shares more insights on what a 1000 calorie deficit does to your body.

How safe is a 1000 calorie deficit?

A 1000-calorie deficit can be safe for short-term (4-12 weeks) weight loss in adults, but over the long term (6-12 months), it could lead to nutritional deficiencies and a slower metabolism. When it comes to teenagers, it’s generally not recommended to maintain a daily 1000-calorie deficit due to their need for essential nutrients to support growth and development.

Seniors and individuals over 50 should also be cautious, as a 1000-calorie deficit may increase the risk of muscle loss and nutritional deficiencies. According to a study conducted by the Department of Family Medicine at Seoul National University Bundang Hospital, a more sustainable approach for weight loss is to aim for a moderate deficit of 500-750 calories.

How safe is a 1000 calorie deficit when combined with intense exercise?

Combining a 1000-calorie deficit with intense exercise increases the risk of overtraining, muscle loss, and potential injury, according to a 2023 review by Tom Anthonius Hubertus Janssen and colleagues at McMaster University.

The study suggests that very low-calorie diets can impact lean mass negatively. If you’re thinking about trying this approach, it’s crucial to incorporate resistance exercise at least twice a week and ensure you’re getting an adequate protein intake of 0.8 grams per kilogram to help prevent muscle loss. For athletes in training, maintaining a 1000-calorie deficit can significantly impact performance and recovery, so it’s advisable to seek guidance from a sports nutritionist.

How safe is a 1000 calorie deficit for someone with pre-existing health conditions?

For someone with pre-existing health conditions like Type 2 diabetes, a 1000-calorie deficit can lead to significant improvements in glycemic control and weight loss, as shown in a 1997 study by F Capstick and the team at the Diabetes Centre, Royal Prince Alfred Hospital, Sydney.

However, it’s crucial to do this under medical supervision, especially since the study also indicated that insulin therapy and medication dosages were adjusted. For post-menopausal women, a 1000-calorie deficit may lead to accelerated bone density loss and is generally not advised without medical guidance.

How long can you sustain a 1000 calorie deficit safely?

You can generally sustain a 1000-calorie deficit for a short-term period of about 4 to 12 weeks, but it’s crucial to keep an eye on physiological, behavioral, and clinical indicators. A 2005 study titled “Long-term weight loss maintenance” by Rena R Wing and Suzanne Phelan indicates that around 20% of overweight people successfully maintain long-term weight loss. So, if you’re considering a 1000-calorie deficit, adopting strategies from successful long-term weight loss—like consistent physical activity and eating patterns—could boost your chances of keeping that weight off.

“Higher energy deficits may lead to several physiological changes that may encourage weight regain,” says an endocrinologist and head of the Obesity Research Group at the University of Melbourne, Priya Sumithran, MD.

“Changes in energy expenditure, metabolism, and hormone pathways involved in appetite regulation, can persist, even beyond the initial weight loss period”.

Dr. Sumithran

What happens when you maintain a 1000 calorie deficit a day?

Maintaining a 1000-calorie deficit per day has both pros and cons, including potential weight loss, a decrease in fat stores, as well as risks like muscle loss, metabolic adaptation, and fatigue.

  1. Weight loss: Maintaining a 1000-calorie deficit a day primarily leads to weight loss, specifically targeting body fat as your body taps into stored fat for energy. According to a study published in the Annals of Nutrition and Metabolism in 2007, led by B Strasser from the Medical University Vienna, the energy deficit alone, regardless of the method used, is responsible for weight reduction. However, keep in mind that while you’ll shed pounds, your metabolism may slow down to conserve energy, potentially hitting a weight loss plateau.
  2. Decrease in fat stores: Maintaining a 1000-calorie deficit a day leads to a significant decrease in fat stores, as your body starts using stored fat for the energy it’s not getting from food. According to a 2014 study by Sayed Hossein Davoodi in the International Journal of Preventive Medicine, significant fat loss can begin as early as four weeks into a calorie-restricted regimen.
  3. Muscle loss: Maintaining a 1,000-calorie deficit a day can lead to muscle loss, which isn’t great if you’re trying to preserve lean body mass. According to a 2017 study published in Advances in Nutrition Journal by researchers from the Center for Human Nutrition at Washington University School of Medicine, diet-induced weight loss reduces muscle mass without necessarily affecting muscle strength. This can increase your risk of sarcopenia, a condition marked by low muscle mass and impaired muscle function.
  4. Metabolic adaptation: When you maintain a 1000-calorie deficit a day, you trigger metabolic adaptation, which means your body gets smarter about saving energy. Essentially, your metabolism slows down more than you’d expect based just on your smaller body size, making weight loss more challenging over time. According to a 2021 study in the American Journal of Clinical Nutrition by Katie L. Whytock, people on a low-calorie diet who experienced less than expected weight loss also saw a significant drop in their daily energy expenditure, confirming this metabolic adaptation.
  5. Fatigue: Maintaining a 1000-calorie deficit a day can lead to fatigue as one of the side effects. According to a study published in Antioxidants & Redox Signaling by Leanne M. Redman and Eric Ravussin from the Pennington Biomedical Research Center, calorie restriction impacts physiological and psychological outcomes, which include energy levels. So, don’t be surprised if you feel tired or low-energy when you’re running on such a big calorie deficit.
  6. Constipation: Maintaining a 1000-calorie deficit a day can lead to constipation, as seen in a study published in the International Journal of Obesity by Astrup, Vrist, and Quaade from the University of Copenhagen. The study found that bowel movements decreased from an average of 1.9 per day on a regular diet to just 0.7 per day on a very low-calorie diet.
  7. Feeling cold: Feeling cold when you’re on a 1000-calorie deficit is backed by science, specifically a study from Washington University School of Medicine in St. Louis. This research, published in Aging (Albany NY) in 2011, showed that long-term calorie restriction led to a sustained reduction in core body temperature. In layman’s terms, your body turns down the heat to save energy, which can make you feel colder than usual.

Who should consider doing a 1000 calorie deficit?

If you’re significantly overweight, an athlete in the off-season, or have a time-sensitive goal like a wedding, a 1000-calorie deficit could be an option. However, teenagers, pregnant women, and those with certain pre-existing health conditions should generally avoid it.

How to do 1000 calorie deficit

To do a 1000 calorie deficit, follow the steps below.

  1. Calculate your TDEE to determine your daily 1,000-calorie deficit.
  2. Design a 1,000-calorie deficit meal plan.
  3. Avoid common mistakes people make when aiming for a 1,000-calorie deficit and not losing weight.
  4. Set expectations for how much weight you will lose on a 1,000-calorie deficit.
  5. Understand the risks of a 1,000-calorie deficit.
  6. Decide if combining a 1,000-calorie deficit with exercise is the right approach for you.
  7. Monitor your progress with regular weigh-ins and body measurements.
  8. Consider how sustainable a 1,000-calorie deficit is for your lifestyle.
  9. Consult a healthcare professional for personalized advice and to rule out any underlying health issues.

How to calculate a 1000 calorie deficit?

To calculate a 1,000-calorie deficit, first find your Total Daily Energy Expenditure (TDEE) using the following TDEE calculator. This gives you an estimate of how many calories you burn in a day. Then, subtract 1,000 calories from that number to find your daily caloric intake target. For example, if your TDEE is 2,500 calories, aim for a daily intake of 1,500 calories to achieve a 1,000-calorie deficit. The following is the 1000 calorie deficit calculator.

1000 Calorie Deficit TDEE Calculator

Please enter your height, weight, age, and activity level:

Height (cm):

Weight (kg):


Activity Level:

What is the 1000 calorie deficit meal plan?

A 1000-calorie deficit meal plan is a 7-day menu that outlines your diet strategy, where you consume 1,000 fewer calories than your daily caloric needs to maintain your current weight.

Day 1

  • Breakfast: Greek yogurt with a handful of berries
  • Lunch: Grilled chicken salad with veggies
  • Dinner: Veggie stir-fry with brown rice
  • Snack: Apple

Day 2

  • Breakfast: Scrambled eggs with spinach
  • Lunch: Turkey sandwich on whole-grain bread
  • Dinner: Baked fish with steamed broccoli
  • Snack: Baby carrots

Day 3

  • Breakfast: Smoothie with banana, protein powder, and almond milk
  • Lunch: Veggie burger with a side salad
  • Dinner: Chicken and vegetable kebabs
  • Snack: A small orange

Day 4

  • Breakfast: Overnight oats with almond milk
  • Lunch: Quinoa salad with mixed veggies
  • Dinner: Spaghetti squash with marinara sauce and a side of steamed green beans
  • Snack: Cucumber slices

Day 5

  • Breakfast: Avocado toast on whole-grain bread
  • Lunch: Lentil soup with a side of whole-grain crackers
  • Dinner: Grilled steak with asparagus
  • Snack: A small peach

Day 6

  • Breakfast: Chia pudding made with coconut milk
  • Lunch: Chicken Caesar salad
  • Dinner: Shrimp stir-fry with zucchini noodles
  • Snack: A small pear

Day 7

  • Breakfast: Fruit salad with a dollop of cottage cheese
  • Lunch: Tuna salad with mixed greens
  • Dinner: Vegetable curry with a small portion of rice
  • Snack: A handful of grapes

What are the common mistakes people make when starting a 1000 calorie deficit?

Common mistakes people make when aiming for a 1000-calorie deficit, as highlighted in “Maintenance of lost weight and long-term management of obesity” by Kevin D. Hall, Ph.D., and Scott Kahan, M.D., include the following:

  • Underestimating calorie intake
  • Neglecting nutrient quality
  • Focusing just on calorie count, which could result in nutrient deficiencies
  • Overdoing exercise to a point where it’s unsustainable or causes injury

How much weight can you lose with a 1000 calorie deficit?

With a 1000-calorie deficit, you can generally expect to lose around 2 pounds a week. That’s because 3,500 calories equals about one pound of fat, and 7 days of a 1,000-calorie deficit equals 7,000 calories, or 2 pounds. Doubling the deficit to 2000 calories daily could lead to losing around 4 pounds a week, but it’s not recommended for most people as it can be extreme and unsafe.

Even without exercise, sticking to a 1000-calorie deficit still gets you losing about 0.9 kilograms a week. A 1000-calorie deficit plus regular exercise could potentially lead to more than 0.9 kg of weight loss a week, depending on how many extra calories you burn.

How much weight can you lose in a month if you maintain a 1000 calorie deficit daily?

Maintaining a daily calorie deficit of 1000 calories can result in approximately 3.6 kg (around 8 pounds) of weight loss within a month. However, it’s important to note that such calculations have limitations as numerous factors come into play, including your daily lifestyle, injuries, stress, travel, celebrations, and dining out. Additionally, the initial weight loss often includes the shedding of water weight.

By consistently maintaining a 1000-calorie daily deficit over six months, you can expect to lose approximately 21.6 kg, which is roughly equivalent to 48 pounds. These calculations are grounded in the general guideline that a 3500-calorie deficit typically results in about a 0.45 kg or 1-pound weight loss.

What can cause someone to not lose weight on a 1000 calorie deficit?

There are several possibilities why you’re not losing weight on the 1000 calorie deficit.

  • Metabolic Adaptation: Even when you’re in a 1000-calorie deficit, your body can experience metabolic adaptation, which reduces your calorie-burning rate to conserve energy. This phenomenon was observed in a 2017 study conducted by David Benton and Hayley A. Young at Swansea University, titled “Reducing Calorie Intake May Not Help You Lose Body Weight.”
  • Water Retention: Even when maintaining a 1000-calorie deficit, water retention might become a concern, concealing your actual weight loss progress. This can be triggered by factors such as high sodium intake.
  • Calorie Miscalculation: You might think you’re in a 1,000-calorie deficit, but in reality, you could be miscalculating calories. Studies have shown that people often underestimate calorie intake by 20-40%. The USDA Center of Nutrition Policy conducted a fascinating study that compared people’s perceptions to the actual servings of foods, as depicted in this diagram.
how much people eat on 1000 calorie deficit

Other potential reasons for not losing weight despite a 1000 calorie deficit include your exercise possibly increasing your appetite, which can lead to consuming the calories you burned. Hormones like leptin might disrupt your appetite and metabolism, while your body may compensate by altering the types of foods you crave, resulting in the consumption of more calorie-dense items.

What are the safer alternatives to a 1000-calorie deficit?

A safer alternative to a 1000-calorie deficit is to aim for a 500-750 calorie deficit per day. This range is supported by studies, such as the one from Seoul National University Bundang Hospital published in the Journal of Obesity & Metabolic Syndrome, and is recommended for sustainable weight loss. It is also endorsed by multiple obesity societies and guidelines.

How does a 500-calorie deficit compare to a 1000-calorie deficit in terms of safety?

A 500 calorie deficit is generally considered safer and more sustainable for long-term weight loss compared to a 1000-calorie deficit. According to a study by Robert A. Carels and colleagues from Bowling Green State University, individuals who maintained an average energy deficit of at least 500 calories per day lost nearly four times as much weight as those with a lower daily deficit. The study also emphasizes the importance of self-monitoring daily energy intake and expenditure for effective weight loss.

Is a 1000-calorie deficit too much?

Yes, a 1000-calorie deficit is generally considered excessive for most people in the long term. Not consuming enough calories can pose additional challenges for women, such as hormonal imbalances, with such a significant reduction in calories.

Is a 1000 calorie deficit too fast for fat loss?

Yes, a 1000 calorie deficit can cause you to lose more than just fat; you could also be shedding lean muscle mass. Maintaining such a high deficit can be tough and can lead to nutrient deficiencies. Extreme calorie deficits can lead to hormonal imbalances, affecting things like your thyroid and cortisol levels.

Michal Sieroslawski

Michal is a personal trainer and writer at Millennial Hawk. He holds a MSc in Sports and Exercise Science from the University of Central Lancashire. He is an exercise physiologist who enjoys learning about the latest trends in exercise and sports nutrition. Besides his passion for health and fitness, he loves cycling, exploring new hiking trails, and coaching youth soccer teams on weekends.

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