What Will I Lose on an 800-calorie Diet?

Dropping your calorie count down to 800 calories a day may seem like a brilliant weight loss plan — but like anything that seems too good to be true, it is.

Unless you are under a doctor's supervision to ensure that you are getting a full complement of essential nutrients, you are simply starving yourself. This can cause immediate problems in the short run and cause even more serious issues in the long run.

Dropping to 800 calories per day as part of an ​intermittent fasting plan​, however, can keep your metabolism off-balance. Combining those days with ones where you take in higher calorie counts — that have the variety and amount of nutrients you need to function at your peak — can help you realize your weight loss goals.

Sticking to an 800-calorie per day diet may be the right choice for you if you need to lose weight at a rate of more than 2 pounds per week to quickly improve your health, according to the U.S. National Library of Medicine's website, MedlinePlus.

Diets with a calorie count this low, called ​very low calorie diets​ or ​VLCD​ are often prescribed for patients with obesity before surgery, or for people whose excess weight puts them at risk for type 2 diabetes, heart attack or stroke, MedlinePlus explains.

This is not a good choice for sustainable weight loss, however. Keeping your calorie count that low without the supervision of a health practitioner may rob your body of vital nutrients. It is also almost certain that you will gain the weight back once you return to a more normal way of eating, or risk going into starvation mode. MedlinePlus recommends staying on an 800-calorie diet for ​no longer than 12 weeks​.

It is quite likely that many 800-calorie diet success stories come from people who are actually engaging in ​intermittent fasting​. This is a practice whereby people drastically drop their calorie count for one or two days per week or restrict the times of day during which they eat, explains the International Sports Sciences Association (ISSA).

One way to do this, ISSA explains, is to drop down to 800 calories one or two days per week while eating a more normal calorie count the rest of the time. Another way is to eat only between noon and 8 p.m., or another designated time span. This, according to ISSA, keeps your metabolism off balance so that you continue burning calories rather than going into starvation mode, in which your body hoards every calorie you take in because your caveman brain thinks you are experiencing a famine.

Intermittent fasting also helps with weight loss because it is not a restricted diet, ISSA points out. Eating a diet high in leafy green vegetables, fresh fruit, lean proteins, complex carbohydrates and healthy fats in appropriate portions ensures that you are getting the full range of nutrients and are also not feeling deprived.

​Read more:​ How Intermittent Fasting Can Get You Lean

Your nutritional needs change according to what stage of life you are in, explain the experts at the University of California San Diego Health department, but people all require the same basic building blocks for optimal health, no matter how old they are. Broken down into the simplest terms, everyone needs:

• Calories
• Fiber
• Protein
• Exercise

How many calories you need per day can change depending on your age, weight, health and activity level, UC San Diego Health says. Dropping down to 800 calories per day may help you lose weight quickly, but it is not sustainable.

Fiber is crucial for healthy elimination, lowering cholesterol levels and helping you to feel full. Protein is made of amino acids, and everyone should take in 0.5 grams of protein per pound of their weight, relative to how tall they are. People should also, UC San Diego Health advises, engage in 150 minutes of moderately intense exercise every week.

Exercise, according to Concordia University-Saint Paul, is one of the best ways to encourage your body to release excess weight. Not only does exercise burn calories and help you build and maintain muscle mass, but as Concordia University explains, exercise releases ​endorphins​.

Endorphins are pleasure hormones that can help elevate your mood, rewarding your hard work with feelings of well-being. Eight hundred or 900 calorie diet results may be hard to maintain unless you are committed to a regular exercise program.

Concordia suggests that you look into cardio as your preferred form of exercise if you want to lose weight. Walking, jogging, running, aerobics, dancing and swimming are all forms of cardiovascular exercise.

The key is to raise your heart rate and keep it raised for 30 to 45 minutes. If you are sticking to 800 calories per day, choose a more gentle cardio workout, such as walking or swimming, so that you do not risk becoming lightheaded.

​Read more:​ The Best Weight-Loss Exercises You Can Do at Home

One of the risks of a diet so low in calories that it deprives your body of vital nutrients, caution the experts at Rush University Medical Center, is that it can cause hair loss. It is normal, Rush explains, to lose somewhere in the vicinity of 100 hairs per day. That sounds like a lot, but it really is not if you think about how many hairs come out in the shower or in your hairbrush.

One of the main causes of hair loss that is much more noticeable and constant than normal, Rush explains, is a lack of iron in your diet. Along with hair falling out in small clumps, if the level of iron in your blood is too low, you may also experience chills, dizziness and headaches.

The best way to know for sure if you have an iron deficiency is to have your physician do a blood test, Rush advises, because many of these symptoms can also point to a malfunctioning thyroid.

Dark green vegetables such as spinach are an excellent low-calorie source of iron. If you do not want to abandon your 800-calorie diet to take in more iron-rich foods — such as cold-water fish like salmon; eggs; legumes; nuts; seeds; whole grains — you can simply take supplements. Rush advises ​8 milligrams​ of iron per day for men over the age of 18 and ​18 milligrams​ of iron per day for women over the age of 18.