Feature Archive

Lose Weight Fast: How to Do It Safely

Sick of crash diets and fad diets? Follow these healthy tips for rapid weight loss.

By Kathleen M. Zelman, MPH, RD, LD
WebMD Feature

Reviewed by Brunilda Nazario, MD

You've heard it time and again: fad diets don't work for permanent weight loss. But what about those times when you really need to lose some weight fast? It's hard to pass up the promise of crash diets like the Lemonade Diet, Cabbage Soup Diet, or Lose 21 Pounds in 21 Days when your mission is to squeeze into a new outfit in time for a reunion, wedding, or other special event.

So what's wrong with dropping 20 pounds fast so you can wow your friends and family with a svelte new shape?

The truth is that nothing is wrong with losing weight rapidly -- as long you do it the right way, says Michael Dansinger, MD. He's the medical doctor for NBC's The Biggest Loser show, which spotlights quick and dramatic weight loss.

"In theory, one could drop as much as 20 pounds in a week following a very ambitious eating and exercise plan, devoting more than seven hours per week to rigorous exercise, and under a physician's care like we do on the television program," he says.

But even if you can't drop everything to go to weight loss "boot camp," you can safely lose 3 or more pounds a week at home with a healthy diet and lots of exercise, says weight loss counselor Katherine Tallmadge, RD.

In fact, having a goal like looking great at a wedding or reunion can be a great motivator, as long as you follow a weight loss plan that you can keep up after the special event.

But you need to plan ahead and allow enough time to make changes to your shape.

"Don't wait until one week before the reunion to try and lose 10 pounds," advises Tara Gidus, MS, RD, team dietitian for the Orlando Magic.

How to Lose Weight Fast

Losing weight is a simple mathematical formula: You need to burn more calories than you eat. Experts generally recommend creating a deficit of 500 calories per day through a combination of eating fewer calories and increasing physical activity. Over the course of a week, this should yield a loss of about 1-2 pounds of fat.

If you want to lose weight faster, you'll need to eat less and exercise more. Bottom line: 1,050 to 1,200 calories and one hour of exercise a day (but be sure not to dip below this calorie level for safety's sake). On this type of plan, you can expect to lose 3-5 pounds the first week, or more if you weigh over 250 pounds.

"Dieters who follow the plan can lose 2 pounds from diet and 1 pound from exercise each week, and even more if they have more to lose, because the more fat you have to lose, the faster it comes off," says Dansinger.

You may lose even more weight initially if you limit salt and starches.

"When you reduce sodium and cut starches, you reduce fluids and fluid retention, which can result in up to 5 pounds of fluid loss when you get started," explains Dansinger.

Diets for Fast Weight Loss

When it comes to weight loss, calories count the most, says Dansinger. He recommends cutting back to a daily level of 7 calories per pound of your current body weight (which for a 200-pound person, for example, would be 1,400 calories), but no less than 1,050 calories/day (the lowest level that can be done safely at home). Dietitians more typically recommend 1,200 calories as a daily minimum.

Dansinger advocates a diet that minimizes starches, (even healthy whole grains should be controlled), added sugars, and animal fat from meat and dairy foods. For rapid weight loss, dieters should eat mainly fruits, veggies, egg whites, soy products, skinless poultry breasts, fish, shellfish, nonfat dairy foods, and 95% lean meat.

He notes that there are other ways to control calories, such as minimizing total fat, but believes that tends to be more challenging than his suggested weight loss plan.

Other experts interviewed by WebMD recommended tactics including drinking lots of water, eating plenty of protein, and keeping a food journal.

"Eat enough protein and distribute it evenly through your meals to minimize muscle loss and maximize fat loss," says Tallmadge, author of Diet Simple, who also advises clients to swap out carbs in favor of veggies.

American Dietetic Association spokesperson Dawn Jackson Blatner, RD, recommends:

  • Eat plenty of low-calorie vegetables to help you feel full.


  • Drink plenty of water so you don't confuse hunger with thirst.


  • Clear the house of tempting foods.


  • Stay busy to prevent eating out of boredom.


  • Eat only from a plate, while seated at a table.


  • Always eat three meals and one snack daily -- no skipping meals.