What is the 1,000-Calorie Diet, and Does It Work?

Apr 4, 2023
Elina Balode
, nutritionist
What you’ll learn

    If you’re trying to lose weight, you might be tempted to try strict eating regimens, such as the 1,000-calorie diet. After all, you want to lose weight as fast as possible, right?

    It might sound like a good plan, but there’s a catch.

    While drastically cutting your calorie intake and limiting the type of food you eat can help you lose weight short-term, chances are your weight loss won’t last, and you might make your overall health worse.

    This article will explore the 1,000-calorie diet, including its benefits and disadvantages, explain the dangers of fad diets, and show you how you can safely lose weight instead.

    What is the 1,000-calorie diet?

    The 1,000-calorie diet is an eating strategy that drastically cuts the number of calories you consume daily. As its name suggests, it limits your calorie intake to around 1,000 calories each day.

    You’ll mainly be eating low-calorie foods, such as fruits and vegetables, lean meats, and high-fiber foods. With such a high caloric restriction, you may deprive yourself of many essential nutrients, which may harm you over a period of time.

    Here’s an example of what the 1,000-calorie diet may consist of:

    Sample eating plan

    You’ll eat breakfast, lunch, dinner, and a snack:

    • Your breakfast will consist of different foods, such as eggs, toast, and low-fat yogurt, which equate to around 350 calories. This will be your most calorific meal of the day.
    • Lunch will come out to around 300 calories with foods such as sliced turkey and low-fat cheese.
    • Dinner will also come out at around 300 calories and include skinless chicken and green salad.
    • Lastly, your snack can be eaten at any time during the day and will need to be around 80 calories.
    Example of the 1,000 Calorie Diet meal plan

    Note that there are different diet meal plans for the 1,000-calorie diet that vary in food choices. For example, the 1,000 Calorie Mexican American Meal Plan allows you to swap out bread for whole wheat tortillas and sliced turkey for black beans.


    Being on a calorie deficit means you’re eating fewer calories than your body is burning. As a result, you’ll likely end up losing weight.

    However, calorie deficits can have different results for different people. It all depends on the individual — how much they exercise, their basal metabolic rate (BMR), and more.

    And, while the 1,000-calorie diet will help you lose weight short-term, its drastic approach that cuts out a considerable portion of calories isn’t sustainable. As a result, chances are good that you’ll experience significant weight regain once you stop dieting.

    Why are fad diets bad?

    Fad diets or “crash” diets typically help a person lose weight in a very short amount of time.

    Some common characteristics of fad diets include:

    • Promises a quick fix
    • Severely restrictive
    • Strict rules
    • Missing food groups
    • Results in rapid weight loss
    • Promotes less exercise

    Fad diets are harmful since they often cut out key food groups, resulting in dehydration, weakness, low energy levels, brittle bones, and more. Typical fad diets include the 3-Day Diet, Grapefruit Diet, South Beach Diet, and others.

    Instead, many people have adopted calorie counting. Around 13% of U.S. consumers followed a calorie-counting diet in 2022.

    Graph showing which diets U.S. citizens followed in 2022

    While calorie counting does work — if done correctly — cutting your calories by too much can also be considered a fad diet. This includes the 1,000-calorie diet since it reduces your caloric intake excessively and doesn’t allow your body to get all the essential nutrients it needs.

    Experts say the average female adult aged 19 through 30 needs to consume 1,800–2,400 calories daily, while males of the same age need to consume 2,400–3,000 calories.

    This number changes to 1,600–2,200 calories for females between the ages of 31 to 59, and 2,200–3,000 calories for males of the same age.

    The precise number of calories you need to consume will vary depending on your activity level:

    • Sedentary: A lifestyle where you spend much of your time seated — only including physical activity of independent living. For example standing in front of the stove while cooking, walking around in the office, etc.
    • Moderately active: Includes physical activity equal to walking about 1.5–3 miles per day at 3–4 miles per hour (in addition to independent living activities).
    • Active: Includes physical activity equivalent to walking more than three miles per day at 3–4 miles per hour (in addition to independent living activities).

    Eating fewer calories than your recommended average daily intake will help you lose weight. The key, however, is to not cut your calories by too much. A reduction of 500 calories is usually adequate.

    Females shouldn’t cut their calories to lower than 1,200 calories per day and men shouldn't cut theirs to under 1,500 calories.

    Benefits of the 1,000-calorie diet

    Here are some benefits you can get from the 1,000-calorie diet.

    Fast weight loss

    The 1,000-calorie diet is good for losing weight fast. Thus, it can be a quick solution for someone who wants to lose weight for a special occasion, such as a wedding or vacation.

    But how much can you realistically lose in a week with the 1,000-calorie diet?

    It takes burning around 3,500 calories to lose 1lb. Let’s say the median number of calories a person consumes in a day is 2,000 calories.

    This means if you follow the 1,000-calorie diet, you’ll be eating 1,000 calories less per day and 7,000 calories less per week. Therefore, you can lose approximately 2 lbs or 0.9kg per week. Keep in mind the total calories you lose will ultimately depend on your age, gender, and other factors.

    Image showing how many pounds a person can lose on the 1,000 Calorie Diet

    That being said, it’s also worth noting the “weight” you lose isn’t necessarily weight from fat. More likely, putting your body on a high-calorie deficit will result in a loss of muscle mass.

    Also, remember that this diet plan isn’t recommended for extended periods. It should only be used if you want to lose a few pounds quickly.

    Leads to low cholesterol and reduced visceral fat

    A low-calorie diet, such as the 1,000-calorie diet, has been shown to help lower cholesterol in the body, particularly when the food being consumed is healthy and high in fiber.

    In turn, this helps reduce low-density lipoproteins (LDL) — the bad cholesterol that accumulates in your arteries. And, generally with a calorie deficit comes lower fat intake, which can also reduce visceral fat among obese men and women, resulting in healthier organs.

    Visceral fat organ comparison
    (Image Source)

    Now that you’ve seen the advantages of the 1,000-calorie diet, let’s dive into why you shouldn’t consider doing this diet.

    Disadvantages of the 1,000-calorie diet

    Here are the main downfalls of the 1,000-calorie diet.

    Leads to lowered metabolism

    Your body requires calories to function and sustain three main processes:

    • Physical activity: Your body needs calories to fuel your daily activities, such as walking, working out, and even basic body movements.
    • Basal metabolic rate: This refers to the number of calories your body needs to cover essential functions, such as the proper functioning of the brain and heart.
    • Digestion: Your body uses a certain amount of calories to metabolize the food you eat — also known as the thermic effect of food (TEF).

    Thus, eating fewer calories than your body needs over a period of time can cause your metabolism to slow down. In turn, this can contribute to weight gain.

    Additionally, a significant calorie deficit, such as during a crash diet, can cause weight loss to come from both fat and lean muscle. This loss of lean muscle can reduce metabolism since there is less active tissue in the body that requires energy to maintain.

    Causes fatigue and nutrient deficiencies

    Regularly eating fewer calories than your body needs also makes it far more challenging for you to meet your daily nutritional needs.

    For example, severe calorie-restrictive diets may not provide sufficient vitamin D, vitamin B12, or iron. This can lead to anemia or extreme levels of tiredness.

    Overly restrictive diets may also cause a lack of protein, calcium, vitamin A, and magnesium — which can eventually cause health issues.

    Pushes your body into “starvation” mode

    On a diet of just 1,000 calories per day, your body will think it’s in a famine if you keep it up for too long. This means your body will, so to speak, put itself into “starvation mode,” where it’ll slow down in order to hold onto every calorie for as long as possible.

    Warning signs that your body is in starvation mode include a loss of muscle mass, extreme fatigue, and a feeling of constant hunger.

    Exacerbates certain medical conditions

    People with medical conditions, such as gout or type 1 diabetes, may need to follow a specialized diet to help manage their symptoms and minimize the impact of their condition - conditions that may be worsened by a 1000 calorie per-day diet.

    Consuming a very low calorie diet can also be the origin of several health problems, including gallstones, electrolyte imbalances, and gastrointestinal problems, among others. Therefore, it is important to seek guidance from a healthcare professional before embarking on this type of diet to determine if it is appropriate for your individual health status and needs.

    Top warning signs of body starvation mode

    Putting your body in “starvation mode” is counteractive, and what you want when trying to lose weight is a lively, active body that can burn many calories.

    May reduce fertility

    According to the National Library of Medicine, reproductive function is suppressed in women who consume 22–42% fewer calories than needed.

    This is because the ability to ovulate depends on female hormone levels. More specifically, an increase in estrogen and luteinizing hormone (LH) levels is needed to ovulate.

    A reduction in calories can suppress this function. Signs of reduced fertility may include irregular, reduced, or absent menstrual periods. In other cases, women may also experience changes in their sexual function or hair growth.

    While researchers also believe that severe calorie restriction can impact men’s reproductive function, few studies exist on the topic.

    Causes weight gain

    Low-calorie diets aren’t sustainable. Not only does your body need calories and nutrients to function properly, but it also needs enough food to keep you fed and satiated.

    Not eating enough calories can intensify your hunger and make you more prone to binge eating. Binge eating is the consumption of large amounts of food in a short period.

    Therefore, when you cut your calories by too much and neglect feeding your body the proper amount of food it needs, you can end up consuming more food and regaining all your weight (and some extra pounds with it).

    What to do instead of the 1,000 Calorie Diet

    The best way to lose weight safely and successfully is to adopt healthy eating habits and incorporate regular physical activity into your day. A healthy diet won’t only help you with the initial weight loss, but it’ll also ensure you keep the weight off long-term.

    This is why you should consider doing a custom diet specifically designed for your body and nutritional needs. At CertifiedKetoDiet, we specialize in creating personalized meal plans that help you lose weight safely and long-term. You’ll lose weight but still be able to enjoy great food, like our lazy keto meals.

    However, when it comes to dieting, the problem isn’t always the diet “method.” Often, it’s a lack of motivation. In 2021, 19% of U.S. citizens stated that they didn’t eat healthily due to a lack of motivation.

    Percentage of U.S. citizens who don’t eat healthy due to a lack of motivation

    Having someone on your side to help you during your weight loss journey is crucial. It can mean the difference between you succeeding or failing with your weight loss journey.

    At Certified Keto Diet, you can consult with our nutritionists on our app 24/7. This way, you’ll have someone to help you stay motivated throughout your journey. They’ll be there to celebrate different milestones and give you the push you need to reach your weight loss goals.

    FAQs about the 1,000-calorie diet

    How long can I stay on the 1,000-calorie diet?

    For most people, 1,000 calories are too little to obtain enough energy and nutrients to function properly. Therefore, you shouldn’t follow the 1,000-calorie meal plan for more than a week. Otherwise, the diet may end up causing more harm than good.

    Can you exercise on a 1,000-calorie diet?

    Most adults need more than 1,000 calories a day — even if they’re sedentary and tend to spend a large portion of their days sitting at their desks. Therefore, you should avoid strenuous physical activity while on the 1,000-calorie diet.

    Start losing weight today

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