Losing weight with minimal effort sounds like a win-win situation. With ads promising that you can drink your way to a slimmer figure and detoxify your body to boot, liquid diets sound too good to be true -- and often, they are.
What Are Liquid Diets?
Liquid diets control calorie intake by restricting what you eat to mostly or all liquids. How they work varies from product to product. Some liquid diets are fluid only -- fruit or vegetable juices juices or shakes -- that replace all of your meals, taken three or four times a day. These programs are either do-it-yourself options sold over the counter, or medically supervised plans available only through doctors' offices or hospitals.
Other types of liquid diets replace just one or two meals (usually breakfast and lunch) with drinks, but let you eat a healthy, balanced dinner. These diets may also include snack bars for in-between meals.
Do Liquid Diets Really Work?
Liquid diets contain a reduced -- and often significantly reduced -- number of calories. If you eat fewer calories than you burn off, you will lose weight. However, that weight loss may be short-lived. When you drastically reduce the amount of calories you consume, your metabolism slows to conserve energy. Unless you change your eating habits, you'll gain back the weight as soon as you return to your old diet.
Some liquid diets work better over the long term than others. Researchers have found that diets that include both food and liquids can help overweight people control the number of calories they eat with liquid meals and help keep the weight off for several years.
As for the claim by some liquid diets that they can 'detoxify' the system by cleansing it of impurities, there is no evidence to prove it. The body, say experts, is a very sophisticated machine that has its own system of detoxifying through the liver and sweat.
How Safe Are Liquid Diets?
Ideally, liquid diet drinks should contain 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 these nutrients 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, cold intolerance, electrolyte imbalance, and heart damage. A lack of fiber in your diet from not eating whole fruits and vegetables can lead to constipation and other digestive ailments. You also can lose lean body mass if you don't get enough protein in your liquid diet.
Medically Reviewed by a Doctor on 6/23/2012