Diet Shakes: Sipping to Slimness

By Elizabeth Ward, MS, RD
WebMD Weight Loss Clinic - Feature

Reviewed By Charlotte Grayson, MD

You meant to drop a few pounds this spring, but you never got around to eating less and exercising more on a regular basis. With summertime here, you're considering how to shed that extra weight, and fast. Are diet shakes the ticket to a slimmer you? Perhaps.

Don't Miss a Meal; Have a Shake

By Kathleen Zelman, MPH, RD, LD

In an ideal world, nutritious foods would always be available, along with the time to sit down and enjoy a pleasant meal. We all know there are days when you either have to grab something quick or miss a meal. Skipping meals is a recipe for disaster, often resulting in overeating the wrong kind of foods.

When time is at a premium, there's nothing wrong with drinking a "slim shake" for breakfast or lunch. Keep the shakes in your cupboard or desk for those times when you're unable to sit down to a healthy meal.

Look for drinks that average 26-28 calories per ounce. Journal an 8-ounce beverage as a meal-replacement drink, and a 12-ounce one as a meal-replacement shake.

Diet Shakes Pros and Cons

"I prefer people to lose weight on a balanced, low-fat diet that includes lots of fruits and vegetables," says Cathy Nonas, RD, a spokeswoman for the American Dietetic Association and director of Obesity and Diabetes Program at North General Hospital in New York City. "However, I realize that approach doesn't work best for everyone, so sometimes I recommend liquid meal replacements as part of a healthy eating plan."

Other nutritionists disagree. "Whole foods provide a much better balance of nutrients than meal replacements," says Hillary M. Wright, MEd, RD, a nutrition counselor at Harvard Vanguard Medical Associates in Boston. "Plus, using real foods forces you to make choices that help you maintain weight loss in the long run."

Australian researchers writing in the Journal of Nutrition found that diet shakes, also called meal replacements, were just as effective for producing weight loss when compared with conventional, structured weight loss diets. However, study subjects using diet shakes were more favorable about dieting in general, rating their eating plan more favorably for its convenience than those on the regular food diet. That may be just the motivation some people need to diet.

Nonas says diet shakes are particularly useful for jump-starting weight loss (health experts generally recommend limiting weight loss to no more than about 2 pounds a week). As with meal replacement bars or low-calorie entrees, diet shakes help you keep tight control on calories. "They are particularly useful for women who have very little leeway in calorie intake and who can't lose weight when they exceed their calorie quota even by a little," Nonas says.

Of course, diet shakes of any type won't work toward weight loss unless you eat fewer calories than you burn every day. To use diet shakes and meal replacement beverages most effectively, determine a calorie allowance for weight loss. You may be tempted to slash daily intake to 1,200 calories for fast results, but 1,500 calories may help you stick with your eating changes longer. Include exercise, which aids weight control and promotes good health.

Diet Shakes: The Simplest Way to Diet

Diet shakes and other meal replacements are a boon when you lack the time or motivation to shop for and prepare balanced meals. They also help when you just don't want to think too hard about what to eat to lose weight. Even Wright admits they are useful -- to a point. "If you are consistently missing a certain meal, such as breakfast, then a meal replacement shake is better than nothing. That's because studies show eating breakfast fosters long-term weight control."

The makers of some ready-to-drink meals recommend sipping one each for breakfast and lunch, and eating a sensible or healthy low-fat dinner, keeping food preparation to a minimum. You may make it through the day on automatic pilot by relying on diet shakes, but you can't completely escape thinking about calories and other nutrients. Even when diet shakes stand in for two out of three meals, you still need to interpret "sensible" and "healthy low-fat" when determining dinner.

"Dinner is where people who use meal replacement shakes can get into trouble," Nonas says. That's because many people eat at night to relieve tension from the day. Going overboard at dinner (and after) can effectively wipe out the calorie deficits that contribute to weight loss. Limiting dinner to 4 to 5 ounces of cooked poultry, seafood, or lean meat; a medium baked or sweet potato or a 1/2-cup cooked rice or pasta; and a cup of cooked broccoli or other vegetable seems a sensible way of getting nutrients without excess calories.