Calorie restriction is the surest way to lose weight, and there is certainly some science to support it. When you consume fewer calories than your body needs, your body will start to use its stored fat as energy, resulting in weight loss (1).
The typical recommendation is a calorie deficit of 500-1,000 calories per day with an aim of safe and sustainable weight loss of 1-2 pounds per week (2). Your calorie deficit is the difference between the amount of energy you burn in a day and the number of calories you eat. For example, if your daily energy needs are 2,000 calories, but you eat only 1,500 calories, you have a deficit of 500 calories. In theory, this means that consuming only 700 calories a day could potentially result in a significant amount of weight loss over time.
However, such an extreme approach isn’t without its risks and drawbacks.
Let’s take a closer look at the potential effects of consuming only 700 calories a day.
Eating only 700 calories a day falls under very low-calorie dieting (VLCD). According to the NHS UK, a very low-calorie diet is a clinically supervised diet that requires one to eat less than 800 calories in a day (3). It is usually only recommended for people with an obesity-related health complication that would benefit from rapid weight loss. One example may be to prepare for surgery where the risks of the procedure would be reduced by weight loss.
VLCD should not be done without medical supervision. You should also not stick to it for more than 12 weeks. A sudden and extreme reduction of calorie intake sends your body into starvation mode, which can impede long-term weight loss. Later in this article, we address the frustrating paradox that is calorie restriction without medical supervision.
If you’re curious about 3-day fast weight loss, check out our earlier article.
Medically supervised VLCDs often use meal replacements. These are drinks, bars, or soups that have a controlled number of calories and nutrients. They include the right amount of vitamins and minerals to sustain bodily functions (4).
If you take on a 700-calorie-a-day diet without meal replacement, you must count calories. The diet requires a high level of discipline as it is not easy to follow. You must make healthy food choices that ensure that you get all the necessary nutrients. Your doctor or a registered dietitian will work closely with you to make sure you’re doing the diet safely and getting the nutrients you need.
VLCDs can result in rapid weight loss under medical supervision. An obese person may lose approximately 3 to 5 pounds per week on such a diet (6). Over 12 weeks, this could mean 36 to 60 pounds.
As a result of significant weight loss, some medical conditions related to obesity may improve. Diabetes, high cholesterol, and high blood pressure may be significantly improved through a combination of VLCD and medication (7).
The long-term results of going on a 700-calorie diet vary. Weight regain is possible (8).
However, when combined with exercise, therapy, and follow-up treatment, medically supervised diets can have long-lasting effects. If you go on a low-calorie diet, you must also be willing to maintain a healthy lifestyle after you achieve your target weight.
Read more: Weight Loss for Seniors Over 70 – All the Secrets Uncovered
If you were on a 700-calorie diet, your meals would look something like this:
or this:
or even this:
Depending on personal food preferences, the meals may vary in terms of calorie count. As you can see, the portion sizes are significantly reduced compared to a regular meal plan.
Read more: Are the Best Diet Shakes for Weight Loss Effective?
When you start eating 700 calories a day, you may experience some side effects. The most common ones are (8):
These symptoms are brought on by changes in your body. According to the Dietary Guidelines for Americans, the average adult needs 1,600 to 3,000 calories per day (9). Although the exact number of calories needed varies based on age, sex, and physical activity, 700 is incredibly low for any adult.
To put things into perspective, a 2-year-old needs around 1,000 calories in a day (9). So, when you go on a 700-calorie diet, you can expect your body to go through several changes. These changes may produce unpleasant symptoms that go away after a few days.
Below is what happens to your body over time on a VLCD, which is why medical supervision is so important:
When you restrict calorie intake, your body turns to glycogen stores for energy. Glycogen is stored in your muscles and liver. Each gram of glycogen is stored with at least 3 grams of water (10); burning it results in water loss.
Medically controlled VLCDs emphasize water intake. So, if you want to go on a 700-calorie diet, it’s important to drink enough water. Staying hydrated makes up for the water loss that is caused by glycogen depletion.
In a small older study by researchers at Newcastle University, 11 people with diabetes reduced their daily calorie intake to 800 per day for 8 weeks. After three months, 7 of the 11 participants were diabetes-free (11).
During the study, it was noted that the participants’ pre-breakfast blood sugar levels were close to normal. Generally, the blood sugar levels for those on calorie restrictions were lower than those in the control group.
The researchers theorized that the VLCD prompted the body to use up fat clogging the pancreas. As a result, it helped revive insulin-producing cells in this small number of people with type 2 diabetes. Consequently, blood sugar levels decreased, even beyond the duration of the diet itself, as long as weight loss was maintained (12).
Depending on the diet you follow, you may not get a steady supply of macros during the day to keep your blood sugar levels steady. Cleanses are notorious for causing blood sugar spikes and drops due to the regular intake of juice with high sugar and low fiber content.
The stability of your blood sugar and insulin levels while on a 700-calorie diet depends on what you eat. Eating healthy, balanced meals, albeit small portions, can help prevent negative outcomes. If you take medication that affects your blood sugar, you’ll need to work closely with your doctor and check your blood sugar often while on a low-calorie diet.
According to research, rapid weight loss often results in loss of muscle mass (13). So if you go from consuming more than 2,000 calories to only 700, your muscles may start to break down. This is because in addition to stored fat, your body first breaks down glycogen, then protein for energy, in the absence of carbohydrates.
Don’t underestimate the dangers of muscle loss. Your heart is a muscle that can be affected by rapid weight loss. This emphasizes the need for balanced nutrition and close medical supervision while on a 700-calorie diet.
As your body mass decreases, your basal metabolic rate (BMR) drops (14). Daily activities take up less energy. Your body also adapts to there being less energy available.
If you feel lethargic, you’ll move around much less. Eventually, your metabolism drops so low that weight loss plateaus. This reaction is partly because your brain registers starvation and triggers your body to conserve calories. It may take weeks of continuous consumption of fewer calories for your metabolism to slow down in this way.
Following a 700-calorie diet for long enough can lead to malnutrition and more serious effects such as permanent organ damage (15). This could happen even faster if your diet is unbalanced.
For example, you may cut out calories from fats to meet your daily target. However, fats are important for the absorption of certain vitamins, and fats themselves play important roles in our bodies. By extension, you’ve denied your body essential nutrients.
When your body gets to a malnourished state, resuming your normal diet abruptly can cause refeeding syndrome. Refeeding syndrome is characterized by a drastic drop in phosphorus, magnesium, and potassium levels that can result in heart failure.
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You’ve been eating 700 calories a day for 2 weeks, but the scale won’t budge. Understandably, you’re frustrated. Everyone’s body is different so there it is hard to pinpoint the reason for your weight loss plateau. However, any of the reasons below could explain why you are not losing weight despite being on a 700-calorie-a-day diet.
When you drop your calorie intake rapidly, your brain interprets it as starvation. To keep you alive, it triggers your body to slow down and burn fewer calories (16). On a low-carb diet, the body turns to protein for fuel. This often results in loss of muscle mass.
Muscles burn more calories than fat (17). So if your muscle mass to fat mass ratio is low, you burn fewer calories each day. Each of these factors can come together to frustrate your weight loss attempts.
Perhaps you’re frustrated because you’re not actually on a 700-calories-a-day diet. Even if you’re being incredibly careful with your food choices, it’s easy to forget that condiments contain calories.
A tablespoon of ketchup has 18.5 calories (18), while a tablespoon of mayonnaise has 94 calories (19). These calories count, particularly when you can’t eat more than 700 calories in a day. They could be making you consume far more than you think.
Dining out while following a very low-calorie diet can distort your calorie consumption pattern. You’ll never know what exactly is in your meal. Although the restaurant may provide nutritional information, most are just estimates. The restaurant staff don’t weigh and measure each ingredient accurately.
You may feel like treating yourself to a nice meal once in a while, which is okay. But never think that while dining out you know exactly how many calories you’re consuming. If you’re on a very low-calorie diet, you should avoid dining out. Meal prepping and cooking at home is advisable. You should only be on the diet for a short period of time.
You discover a fantastic snack that’s “light” or “low” in calories. Although this seems too good to be true, you trust labels and include the snack in your daily intake. Unknown to you, the snack has more calories than you thought.
Always trust your instincts when it comes to calorie counting. If a health claim on a label seems too good to be true, it probably is. Health claims on labels aren’t always accurate. Check the nutrition facts label for calorie information and pay attention to the serving size.
Do you think you can manage a 700-calorie diet by eyeballing your food? Think again. Your portion estimates could be incredibly inaccurate, particularly if you don’t weigh food. Strict calorie counting requires a food scale, proper meal prep, and preparation.
Your portion sizes could also be distorted by packed foods that claim to be single servings. Depending on the calorie count, 1 serving according to the package could be 2 or 3 for you on your VLCD. Remember that manufacturers base their serving sizes on recommended daily intakes for healthy adults. To see results while eating 700 calories a day, you must focus on the accuracy of your portions.
Did you know that companies are allowed to label foods with less than 5 calories per serving as “zero-calorie”? (20) This applies to salad dressings, sweeteners, and cooking sprays. So, you may be consuming multiple servings of a certain food, assuming that it is “zero-calorie” when in reality, it’s adding to your daily intake.
As always, moderation is key when it comes to food. No matter what the label says, don’t eat too much of one item.
Are you looking for some ideas of what to cook while on a 700-calorie-a-day diet? Below are some breakfast, lunch, and dinner meal ideas you can use. Your meal plan should take into account daily macros intake.
The ideal breakfast on a 700-calorie diet is energizing, quick to prepare, and low in calories.
Uncover the surprising benefits of the smoothie to lose belly fat in 1 week in our past article.
A filling lunch gives enough energy to carry out daily activities.
Make sure you get enough nutrients by having a light, nutrient-packed dinner.
Eating 700 calories a day can help you lose weight under medical supervision, but so can burning the same amount of calories through exercise. The exact number of calories you burn through exercise depends on several factors such as age, sex, and weight.
According to Harvard Health, these exercises burn the most calories for a person who weighs 155 pounds (21).
If doing one activity continuously for an hour seems too boring for you, you should consider high-intensity interval training (HIIT). HIIT combines short bursts of intense exercise with rest or lower-intensity exercise. Any workout can be customized to HIIT. For example, a walk can include exercise such as squats every few minutes. Running on the treadmill on an incline at varying speeds is also a HIIT workout.
HIIT workouts are efficient as they take advantage of the body’s natural fat-burning capabilities (22). They don’t require any equipment, which makes them easy to do anywhere. Furthermore, they’re the key to improving your cardiovascular health. As they split the workout into intervals, they’re more interesting than hour-long sessions doing one exercise.
For more details about the best weight loss program, take a look at our prior publication.
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Consuming less than 1,200 calories per day for women and 1,500 calories per day for men is generally considered too low and may not provide sufficient nutrients for most people. Healthy calorie intake guidelines can vary based on several factors, including age, sex, activity level, and overall health goals. However, here are some general guidelines (9): Adult Women: Typically need 1,800 to 2,400 calories per day. Adult Men: Generally require 2,200 to 3,000 calories per day. Children and Adolescents: Calorie needs vary widely based on age, growth, and activity level, ranging from 1,000 to 3,200 calories per day. Older Adults: May need fewer calories due to decreased activity levels and metabolic rate, usually 1,600 to 2,200 calories per day. These are general estimates, and individual needs can vary. It’s important to focus on a balanced diet that includes a variety of nutrients and to adjust your calorie intake based on personal health goals and lifestyle. While it may be possible to survive on 500 calories a day for a time, it isn’t recommended for long-term health. Consuming such a low amount of calories can lead to nutrient deficiencies and potential health complications. It’s important to consult a healthcare professional before drastically reducing your calorie intake. One exception to this is intermittent fasting, where you alternate between periods of eating and fasting. This approach has shown some promising health benefits (23), but it should be approached with caution and under medical supervision. Alternate day fasting (ADF) is a form of intermittent fasting that involves consuming only 500-800 calories on fasting days (24). While it may result in weight loss, ADF is still considered extreme and shouldn’t be done without refeeding days where your calorie intake is increased.FAQs
How many calories are too low?
Can you survive on 500 calories a day?
Eating 700 calories a day should only be done under the guidance of a medical professional. Your body needs more than 1,200 calories a day, so consuming 700 is an extreme calorie restriction. Despite being a very low-calorie diet, the 700-calorie diet can work. If done correctly, it can lead to rapid weight loss, which is sometimes required for obesity-related health conditions.
To achieve weight loss on 700 calories a day, you must monitor your intake correctly. Avoid dining out and snacking on foods with a lot of calories per serving. Most importantly, work closely with your healthcare provider throughout the process. If the diet seems too complicated for you, try exercise. You can burn an extra 700 calories a day by combining workouts of varying intensity.
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