$20 billion spent on diets

When you're trying to lose weight, the number that seems to matter most is the one you see on the scale. But there are plenty of other compelling numbers coming out of the growing weight-loss industry. Check out a few below and 

$20 Billion

The annual revenue of the U.S. weight-loss industry, including diet books, diet drugs and weight-loss surgeries.

108 Million

The number of people on diets in the United States. Dieters typically make four to five attempts per year.

85 Percent

The percentage of customers consuming weight-loss products and services who are female.

1 Hour

The amount of time spent on daily exercise by people who lost and kept off at least 30 pounds of excess weight for five years.

220,000

The number of people with morbid obesity in the United States who had bariatric surgery in 2009.

$11,500 to $26,000

The average cost of bariatric surgery, which reduces the size of the stomach.

$500,000 to $3 Million

The average salaries paid to celebrity endorsers of major weight-loss programs.

$33,000

The amount of money celebrity endorsers, on average, earn per pound lost.

$5,594

Cost for a week-long (six night) weight-loss program at Beau Rivage Palace, a luxury hotel in Lausanne, Switzerland. The program includes massages and personal training sessions and discourages deprivation.

2

The number of glasses of wine per day allowed to guests of the Beau Rivage Palace weight-loss program.

Sources: John LaRosa of MarketData; National Weight Control Registry; American Society for Metabolic and Bariatric Surgery; Jo Piazza, author of "Celebrity Inc.: How Famous People Make Money."

watch the full story on the "Losing It: The Big Fat Trap" on "20/20" online.