In 1974, at age 60, Jack LaLanne swam from Alcatraz Island to Fisherman's Wharf, handcuffed and shackled, towing a 1,000 pound boat. That's mucho macho!

Fortunately you don't have to go to such extremes to be a healthy guy with healthy swimmers. But if you're packin' even a few extra pounds (around 74 percent of guys in North America are overweight), your swimmers could use some help!

A new study from Stanford University found that the larger a man's waist circumference and the higher his body mass index, the lower his semen level, and therefore his sperm count. Men with a healthy BMI (somewhere between 18.5 to 24.9) typically ejaculate about 3.3 ml of sperm-containing semen. Men with a higher BMI produce less semen for sperm to swim in - around 2.8 ml. And you can get only so many swimmers into that size pool!

So, to make the pool (and your sperm count) bigger, here's what you need to do:

1. Eat 300-500 fewer calories a day. That equals about 1 American beer (145), a chocolate chip cookie (160) and one cup of sugary cereal (110) with 1/2 cup of whole milk (75). And eliminate the Five Food Felons.

2. Get sweaty! The most-effective, least-expensive way is a walking routine with interval training. So put on your walking shoes (10,000 steps a day is your goal) and walk 100 steps a minute for 10-15 minutes; then go for 2.5 minutes of intense walking at 130 steps per minute. Repeat as often as you can.