If you’re over 35 and your diet routines aren’t working anymore, take a look at your metabolism. Good Housekeeping says you can boost the number of calories your body burns by focusing on a few fixes.

"Your metabolism is slowing as you age and you are actually losing muscle," said Jenny Cook, executive editor, Good Housekeeping. "So even though you're eating the same amount, and you might be exercising the same amount, you're gaining weight. There are several things you can do to improve your situation. One is get a body fat reading. You can get one at a local gym."

Using a skin-fold caliper is the traditional way of testing body fat, according to Nikki Carosone, manager at The Club@Hearst. "I'm going to pinch somewhere right in the middle of the upper arm. Typically we just use a tape measure and hold the spot to test the body fat. You want to pull the skin away from the muscle to get the most accurate reading. Then we would do that three times."

"If your reading is 30 percent or higher, that's a real wake up call to make some healthy changes," added Cook.

If you never challenge your muscles with strength training, you can lose up to five pounds of muscle each decade. "You really need strength training such as working out with weights to create more muscle and to preserve muscle. The reason that weight training works is that it creates tiny tears in the muscle that then encourage them to rebuild themselves stronger, create more muscle and burn more calories," Cook explained.

Skipping or skimping on breakfast to lose weight? Good Housekeeping says that's a misconception. "Research shows that eating breakfast is a key strategy for losing weight. In fact, a University of Texas study found that people who ate breakfast ate 100 to 200 calories less during the day," said Delia Hammock, R.D., nutritionist, Good Housekeeping Institute.

A final note: Good Housekeeping says drinking green tea can also rev up your metabolic rate by up to 3.5 percent. That’s because of its caffeine and plant nutrients. To learn more, check out the April issue of Good Housekeeping or visit www.goodhousekeeping.com.