fit info

March 18, 2007

Don't blame metabolism for weight gain

This article appeared in the Reno Gazette Journal just this past week. This is such an excellent article, that I am putting it on the SWAC Fitness Info Page this week so that everyone reads it! There are many myths and questions out there about metabolism. This article truthfully points out the bottom line: in order to lose weight, you have to take in fewer calories than you burn!~Christine

http://news.rgj.com/apps/pbcs.dll/article?AID=/20070313/HEALTH/703130310/1092

CONNIE MIDEY GANNETT NEWS SERVICE

Metabolism is not often -- or at least not to any great extent -- the weight-gain villain dieters accuse it of being.

Nor is it always the hero responsible for some people's ability to maintain a trim figure despite prodigious eating habits.

"People's metabolic rates can be different," said Dr. Marshall Block of Endocrinology Associates in the Phoenix area, "but not so different that it accounts for the vast amount of obesity present in our society. Everyone pretty much agrees that the majority of obesity is due to excess caloric intake, not to a decrease in metabolic rates."

For a subject so much a part of everyday conversations about weight management, metabolism and claims about amping up its power continue to confound us.

Block defines it as "the sum of all the chemical reactions that occur inside the body to either create energy or use energy and make the products that the body needs to function."

Think of metabolism as your body's engine -- one that never shuts down -- and food as the fuel.

Calories from the food you consume provide energy for everything your body does, and they burn at a pace determined in part by your activity level, muscle-to-fat ratio and basal metabolic rate.

Basal metabolism is expressed in the number of calories needed for basic functions performed even while you're at rest: breathing, circulating blood, growing and repairing cells, maintaining organ function and so on.

These basic needs account for about 60 to 75 percent of the calories you burn each day, a number that remains fairly consistent. It's the number of calories you'd use if you stayed in bed all day.

Eating and processing food burns about 10 percent of calories expended daily, with physical activities responsible for the rest. Take in more calories than you burn, and the excess is stored as fat.

Yes, out-of-whack metabolism could be behind the five or 10 pounds that caught up with you and now won't let go, said Tosca Reno, author of The Eat-Clean Diet (Robert Kennedy Publishing, 2006, $16.95, paperback).

"But it's probably out of whack because we did it to ourselves," she said from her home near Toronto. "We're sort of globally responsible for trashing our metabolism."

Reno cites poorly spaced meals, out-of-control portion sizes and neglect of strength-building exercises as a few of the culprits. Serious metabolic and endocrine diseases that contribute to significant weight gain are uncommon, she said. At his offices, physician Block sees just one or two people a year with Cushing's syndrome, for example.

The syndrome, characterized by increased fat in the face, neck and upper body and thinning in the rest of the body, can account for 10 to 20 pounds in excess weight, he said. The condition requires medical treatment that may include surgery, radiation, chemotherapy or cortisol-inhibiting drugs.

The more commonly seen hypothyroidism, or underactive thyroid, slows metabolism and can cause weight gain, Block said. About 10 to 15 pounds is typical.

"For patients diagnosed with hypothyroidism, a lot of the weight gain is due to water retention, and as soon as you give them thyroid pills, that weight is lost," he said. "People who are 100 pounds overweight and blame their thyroid? They're in left field."

The solution is simple, but not as effortless or fast as suggested by people promoting what they call metabolism-revving pills, foods and programs, Block said.

"In order to lose one pound of fat, you need to burn approximately 3,500 calories," he said. "You can do that in one week by cutting 500 calories a day from your diet or exercising enough to burn 500 calories a day, or by (a balance of) both."

METABOLISM GETS PLENTY OF BLAME AND PLENTY OF CREDIT FOR ITS ROLE IN WEIGHT CONTROL, AND IN MOST CASES, NEITHER IS ENTIRELY EARNED. HERE'S WHAT EXPERTS KNOW ABOUT MAKING THE PROCESS WORK MORE EFFICIENTLY:

The claim: Slow metabolism is responsible for our gaining weight, fast metabolism for maintaining or losing weight.

What's known: Metabolism influences the body's energy needs, and it works at a similar pace in most people of the same age and sex, slowing during sleep. An imbalance “ created by consuming more calories than you burn”is the biggest cause of weight gain. Metabolic disorders responsible for large weight gains are uncommon, said endocrinologist Dr. Marshall Block. People who eat lots but stay slim may be more active than others realize.

The claim: Metabolic rates are fixed for life by genetics.

What's known: Genes are a factor, but age, muscle-to-fat ratio and activity level also influence metabolism. Starting at about age 40, people's metabolism slows and their muscle mass tends to decrease, reducing calorie needs.

The claim: Men naturally have fast metabolism.

What's known: Men usually have less body fat, more muscle and a higher basal metabolic rate than women. They burn more calories at rest and when they're active.

The claim: Pills can boost metabolism.

What's known: Dietary supplements are only loosely regulated by the Food and Drug Administration, and supplements' claims to jump-start metabolism and burn fat aren't always confirmed in reliable studies. Some supplements contribute to weight loss with ingredients, such as caffeine, that increase activity levels and appetite suppressants that cut calorie intake.

The claim: Hot peppers, other spicy foods and green tea can boost metabolism.

What's known: Small studies suggest that spicy foods and green tea may increase metabolism for a short time after they're consumed. However, processing any food burns calories. Overall good nutrition is what's important, said Tosca Reno, author of "The Eat-Clean Diet." That includes protein (a higher calorie-burner during digestion than other foods) and complex carbohydrates, such as whole grains, fruits and vegetables (which are processed slowly and prevent insulin spikes), she said.

The claim: A strict diet is the only way to lose weight.

What's known: It may produce results in the beginning, but metabolism slows when you eat too little or space meals too far apart, signaling your body that it's facing starvation. John Crow of Core, Life in Balance in Glendale, Ariz., said eating small but frequent meals and snacks is more effective. In a Georgia State University study, athletes who ate a 250-calorie snack three times a day had higher metabolic rates and consumed fewer total calories than athletes who drank a calorie-free beverage instead.

The claim: Exercise can boost metabolism.

What's known: Aerobic exercise, such as walking or running, burns calories and improves cardiovascular health. It's essential for good health and fitness. But add strength training, such as weight lifting or doing "wall push-ups," to your routine, and the effects on your metabolism will be longer-lasting. That's because strength training builds muscle, and muscle requires higher calorie expenditure than fat does “burning 10 to 20 times the calories per pound that fat does, even when you're at rest.

The claim: Knowing your metabolic rate can help you manage your weight better.

What's known: Numbers can be motivators, as can support programs and detailed plans of action. If you don't need that much structure, talk with your doctor about making better food choices and increasing physical activity. But if you're curious, you can get a rough estimate of your basal metabolic rate by multiplying your weight times 10 calories. Remember, the result represents the approximate number of calories needed just to maintain basic body functions while you're at rest, and they vary depending on your sex, age and amount of muscle. Sources: Dr. Marshall Block; Core, Life in Balance; author Tosca Reno; National Institutes of Health; and Cornell University.

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