Losing weight with minimal effort sounds like a win-win situation. But are liquid diets too good to be true?

What Are Liquid Diets?

Like the name suggests, liquid diets mean you’re getting all, or at least most, of your calories from drinks. Some liquid diets are limited to fruit or vegetable juices, or shakes, that replace all of your meals, taken three or four times a day. You do some of these diets on your own. Others need medical supervision. Other types of liquid diets replace just one or two meals (usually breakfast and lunch) with drinks, and then you eat a healthy dinner. You may also get snacks on some of these plans.

Do Liquid Diets Work?

Liquid diets can work, like any diet that gives you fewer calories than you use. These diets also can help by taking the guesswork out of portion control. But the results may not last. When you drastically cut calories, your metabolism slows to save energy. Unless you change your eating habits, you’re likely to regain the weight you lost after you go off the liquid diet. Some liquid diets work better over the long term than others. Diets that include both solid food and liquids can be an effective and convenient way for overweight people to control the number of calories they eat.

How Safe Are Liquid Diets?

Ideally, liquid diet drinks should give you a balance of nutrients you need throughout the day, but that isn’t always the case. Very low-calorie diets (400-800 calories per day) in particular can be lacking in a balance of protein, carbohydrates, fats, vitamins, and minerals you need and should only be used under medical supervision. Missing out on essential nutrients can lead to side effects such as fatigue, dizziness, hair loss, gallstones, and heart damage. Also, if you don’t get enough fiber, because you’re not eating whole grains, fruits and vegetables, you can get constipated. You also can lose muscle if you don’t get enough protein calories in your diet.