The allure of rapid weight loss often leads individuals to explore drastic measures, such as very low-calorie diets (VLCDs). One such diet involves consuming only 700 calories a day. While calorie restriction is a sure way to lose weight that can lead to rapid weight loss, particularly for individuals with obesity-related health complications, it's crucial to understand the potential benefits, risks, and necessary precautions before embarking on such a restrictive regimen.
Understanding the 700-Calorie Diet
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). Eating only 700 calories a day falls under very low-calorie dieting (VLCD). It is usually only recommended for people with an obesity-related health complication that would benefit from rapid weight loss. VLCD should not be done without medical supervision and you should also not stick to it for more than 12 weeks.
Potential Benefits of a 700-Calorie Diet
Rapid Weight Loss
One of the primary reasons people consider a 700-calorie diet is the promise of rapid weight loss. An obese person may lose approximately 3 to 5 pounds per week on such a diet (6). This can be particularly motivating for individuals who need to lose weight quickly for medical reasons, such as preparing for bariatric surgery. A primary utility of a VLCD is to promote rapid weight loss in preparation for patients undergoing, for example, bariatric surgery [3,4]. In addition, VLCDs are often used by athletes who are seeking rapid weight loss for competition (i.e., weight-class specific sports) [5] and individuals who seek very low levels of body fat, such as a bodybuilder or physique athlete during periods of contest-preparation [6].
Improvement in Obesity-Related Medical Conditions
As a result of significant weight loss, some medical conditions related to obesity may improve. VLCDs have been demonstrated to positively affect the health of persons with type 2 diabetes (T2D). The improved prognosis is primarily due to the large energy deficit resulting in rapid weight loss leading to improved glycemic control, insulin sensitivity, and reduced cardiovascular risk factors in obese individuals with T2D [2,42▪▪]. During the study, it was noted that the participants’ pre-breakfast blood sugar levels were close to normal. 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.
Simplified Meal Planning
With only 700 calories to work with, meal planning isn’t overwhelming. On this diet, you quickly understand how much (or how little) you can eat to hit your calorie target. This can lead to a greater awareness of calorie content and portion sizes.
Read also: Achieve Your Weight Loss Goals: 1700-Calorie Diet Explained
Risks and Side Effects of a 700-Calorie Diet
Starvation Mode and Metabolic Slowdown
A sudden and extreme reduction of calorie intake sends your body into starvation mode, which can impede long-term weight loss. 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). As your body mass decreases, your basal metabolic rate (BMR) drops (14). Daily activities take up less energy. 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.
Muscle Loss
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. Don’t underestimate the dangers of muscle loss. Your heart is a muscle that can be affected by rapid weight loss. The main risk from following a VLCD is the potential loss of muscle mass [7]. Preventing/negating muscle mass loss could result in avoiding declines in physical function and strength [10].
Nutrient Deficiencies and Malnutrition
Following a 700-calorie diet for long enough can lead to malnutrition and more serious effects such as permanent organ damage (15). 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. To be healthy, you need a balance of foods from different food groups. It's difficult to get good nutrition and feel satisfied on a very low-calorie diet.
Refeeding Syndrome
When your body gets to a malnourished state, resuming your normal diet abruptly can cause refeeding syndrome.
Side Effects
People on a very low-calorie diet for 4 to 16 weeks report minor side effects such as fatigue, constipation, nausea, and diarrhea. These conditions usually improve within a few weeks and rarely prevent people from completing the program.
Read also: The Power of 100 Calories
Gallstones
Gallstones are the most common serious side effect of very low-calorie diets. Gallstones are more common during rapid weight loss. When the body experiences a calorie deficit, it starts to break down fat for energy. The liver then secretes more cholesterol and when combined with bile, can form gallstones.
Important Considerations for a 700-Calorie Diet
Medical Supervision
Eating 700 calories a day should only be done under the guidance of a medical professional. It is usually only recommended for people with an obesity-related health complication that would benefit from rapid weight loss. VLCD should not be done without medical supervision.
Short-Term Use
You should also not stick to it for more than 12 weeks. These diets are only to be used for a short time and are usually not recommended for more than several weeks.
Meal Replacements and Calorie Counting
Medically supervised VLCDs often use meal replacements. These are drinks, bars, or soups that have a controlled number of calories and nutrients. 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.
Water Intake
Medically controlled VLCDs emphasize water intake. So, if you want to go on a 700-calorie diet, it’s important to drink enough water.
Read also: Metabolism and Weight Loss
Monitoring Macros
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. 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.
Avoiding Dining Out
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. 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.
Being Aware of Hidden 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.
Being Wary of Food Labels
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. 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. 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.
Accurate Portion Control
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. 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.
Resistance Exercise Training
Adding RET to adequate dietary protein intake is also an effective strategy for older adults with metabolic impairments. During a caloric deficit, MPB remains constant, leading to the decline in MPS as the primary mechanism for reductions in lean mass [18,35▪]. It has been demonstrated that combining RET with protein intake spread across multiple feedings per day “rescues” this decline in MPS [36]. When adhering to a VLCD, RET will be the most powerful nonpharmacological stimulus for maintaining muscle mass and attenuating muscle atrophy. When RET is combined with a higher protein intake (∼1.2 g/kg), they work synergistically to promote lean mass sparing during periods of an energy deficit.
Gradual Increase in Calorie Intake After the Diet
Losing weight is only half the battle, keeping it off requires a thoughtful approach. Gradually increase your daily intake by 100-200 calories per week. Focus on whole, nutrient-dense high protein foods. Create a balanced eating and exercise routine that fits your lifestyle.
Alternatives to a 700-Calorie Diet
Exercise
Eating 700 calories a day can help you lose weight under medical supervision, but so can burning the same amount of calories through exercise. 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. 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.
Low-Calorie Diet
These diets usually allow about 1,200 to 1,500 calories a day for women and 1,500 to 1,800 calories a day for men. An LCD is a better choice than a VLCD for most people who want to lose weight quickly. But you should still be supervised by your provider. You will not lose weight as fast with an LCD, but you can lose just as much weight with a VLCD. An LCD may use a mix of meal replacements and regular food. This makes it easier to follow than a VLCD.
Time-Restricted Eating
This diet strategy is becoming more popular. It is often compared to fasting, but the two strategies are slightly different. Time-restricted eating limits the number of hours per day that you can eat. A popular strategy is the 16:8. For this diet, you have to eat all of your meals during an 8 hour period, for example, 10 am to 6 pm. The rest of the time you cannot eat anything. There are some studies that this method can cause rapid weight loss, but there is little information so far about whether the weight loss is sustained.
Intermittent Fasting
Intermittent fasting involves regular periods with no or very limited calorie intake. Intermittent fasting focuses on the time window of eating instead of calorie calculations or macronutrient composition, helping people to restrict food intake without having to count calories and to avoid late-night snacking.