Boosting Metabolism

Your metabolism slows by 5 percent each decade. Compared to age 25, you’ll burn about 100 fewer calories a day at 35 and 200 fewer at 45. Do nothing, and you could gain 8-12 pounds a year. With age, muscle mass diminishes and so does your metabolic rate (the number of calories your body burns throughout the day).
However, there’s plenty you can do to boost the number of calories your body burns every day and thus maintain or even lose weight.

Six biggest mistakes you can make:

Mistake: Relying on Just Your Scale
The basic ones, which only calculate pounds, can’t tell you what percentage of your body weight is lean, calorie-burning muscle and how much is puffy, sluggish fat. The less muscle you have, the fewer calories you’ll burn.
The metabolic difference between a pound of muscle and a pound of fat is dramatic: Muscle burns at least three times more calories. A person who weighs 130 pounds and has a healthy 25 percent body fat will burn about 200 more calories per day than a 130-pound person with about 40 percent body fat.
The Fix: Get an Expert to Weigh In
Visit your local gym (or a fitness center affiliated with a hospital) and ask for a body-fat reading. A good way to check their accuracy: At your first visit, get two measurements within minutes of each other by the same person to see how much variation there is. A little, like 2 to 3 percent, is OK. To track your progress, get rechecked roughly every three months.
You can eyeball your fat level at home, too. “If you can pinch an inch or more of fat at your waistline or upper arm, you’re probably carrying more body fat than you should. Anything over 30 percent should be a wake-up call to make some real changes

Mistake: Crash Dieting
When you slash too many calories, you send your body into starvation mode. Eating fewer than 900 calories a day also prompts your body to burn desirable muscle tissue as well as fat, which slows your metabolic rate even more.
The Fix: Shed Pounds S-L-O-W-L-Y
If you stay within the 1,200- to 1,500-calorie range, for women, you can still slim down — and you’ll lower your metabolic rate only by about 5 percent and about 90 percent of the weight you lose will be fat.
Be sure to include lots of lean protein, such as chicken, fish, or lean beef. Protein contains leucine, an amino acid that seems to protect you from muscle loss during a diet. Skim milk can help even more. Those who downed two cups of fat-free milk soon after their workout built more muscle — and lost more flab — than those who drank soy milk or a flavored-carbohydrate drink.

Mistake: Only Doing Cardio
If you never challenge your muscles with strength-training moves, you’ll lose up to five pounds of muscle each decade. Cardiovascular exercise (like walking, biking, swimming, or sweating through an aerobics class) is great for your health, but it isn’t strenuous enough to build or even preserve much muscle mass.
The Fix: Pump Iron
You should aim for about 40 to 60 minutes of strength training a week. Use the weight room at your local gym, or exercise with dumbbells or resistance bands at home. If you’ve never pumped iron before, sign up for a few sessions with a personal trainer. That way, you’ll learn how to get the most out of each move — without risking injury. And once you’ve been at it for a while, you’ll need to increase the weight or resistance you’re using.

Mistake: Sticking to the Same Exercises
If you always walk the same route, swim laps at one speed, or even have a single strength-training routine, your muscles adapt and become so efficient that they burn fewer calories while you work out. How to tell when it’s time for a change? If any of the following is true: You’re not sweating as much at the end of your routine; you don’t feel that tired after working out; or you’re gaining weight even though you aren’t eating more or exercising less.
The Fix: Switch It Up
Give your metabolic rate a big boost by adding a few short, fast-paced bursts of speed to your regular walking, biking, swimming, or other aerobic routine. The reason: When you push hard in short bursts, it reactivates nerve fibers, builds new capillaries, and forces your body to repair the muscle. All of that burns a tremendous amount of calories — long after you’ve completed your session.
As you grow stronger, add more intervals, and make them longer and more intense.

Mistake: Eating Lightly (or Not At All) Before Noon
Breakfast skimpers and skippers, commit the same metabolic faux pas: eating too little to flip on their metabolism as well as vital “satisfaction switches” in the brain that register fullness in the stomach.
The Fix: Munch on More Food in the Morning
Discovery of a metabolic window of opportunity for appetite control: a hearty breakfast. Study volunteers who ate a bigger meal in the morning went on to eat 100 to 200 fewer calories later in the day. Research showed that those who skipped breakfast were 30 percent more likely to be overweight. The best A.M. filler-uppers: oatmeal, eggs, peanut butter — or anything with fiber and protein.

Mistake: Living a High-Stress, Low-Sleep Life
When things get extra-hectic, your levels of cortisol, a stress hormone, shoot up. And that can trigger cravings for high-fat, high-carb foods. The worst part: Your body also sends that extra fat to your waistline. Sleep deprivation increases the appetite-stimulating hormone, ghrelin, and decreases the satisfaction hormone, leptin.
The Fix: Sleep More, Stress Less
Aim for at least seven hours of slumber most nights. Try meditation — it could keep you in your skinny jeans. Or tie on your sneakers and go for a walk in the park or the woods: Research on the health benefits of nature backs this up: one confirmed that just looking at greenery can improve well-being and produce less stress.