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Healthy Hollywood: Ask Keri Glassman -- Does Metabolism Slow Down With Age?

9 August 2012
Keri Glassman -- Access Hollywood
Keri Glassman -- Access Hollywood

Nutritionist Keri Glassman, who regularly shares her expertise on Access Hollywood and Access Hollywood Live, is answering your nutrition, diet, and health questions.

Want to know which foods to curb sugar cravings? Or, what should you eat before a workout? Ask Keri anything!

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Keri will choose one great question a week to be answered Thursday in our Healthy Hollywood column.

To submit questions for Keri, click HERE!

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This week's question...

"I am 42 and I am eating the same way I did a few years ago and gaining weight. Is my metabolism slowing down? Help!" -- Susanna-Lee H., Austin, Texas

Keri says...

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Metabolism, Your Frenemy?: I hear your pain! Metabolism is an umbrella term for a collection of chemical reactions that takes place in the body. One of these processes includes converting the foods we eat and beverages we drink into energy. The body requires energy (aka burns calories) to do absolutely everything--talking, walking, blinking, breathing - even trying to fit into those skinny jeans! Basil Metabolic Rate (BMR) is the term we use for how much our bodies burn taking care of these actions. Many factors influence our BMR, including size, gender, age, genetics and hormones. BMR is about 60-75% of the Total Energy Expenditure (TEE), which is simply a tally of all the calories you burn in one day. 10% counts toward the energy required for you to digest, absorb, transport, and store the foods you eat, known as the Thermal Effect of Food (TEF). The final factor of the equation is the most variable and the only part you control entirely. Like it or not, these are the calories torched during physical activity, whether you're at the gym or on a walk to work, it all counts and burns calories.

Age Isn't Just a Number: So what does this have to do with aging? As a person gets older, their activity level (the calorie torching you control) tends to decline while their energy intake tends to either increase or flat line. This explains the: "I eat the same now as I did five years ago but can't fit into the same jeans" phenomenon. With a decrease in physical activity, say bye bye to your muscles and hello to stored fat (if more calories are taken in than expended). Muscle tissue is highly metabolically active, while fat mass is highly inactive, thus you burn fewer calories at rest with more fat mass. Yes you will burn more while reading this blog if you have more muscle mass! Experts estimate that with each passing decade, your BMR decreases 2-5% due to this change in body composition. If you put it in terms of calories, after age 20, each decade you burn 150 calories less than you did prior.

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Speed It Up a Little!: While you cannot control the rate at which you age (rats!), here are ways you can take matters into your own hands and counteract the effects of aging and the decline of energy expenditure:

1. Grab a Fork -- Do not starve yourself! It may sound counterintuitive, but eating too few calories will ultimately slow down your metabolism. No matter how much you starve to be thin, your body has a natural tendency to keep you alive. The fewer calories you consume, the less your body burns doing the things you can't control, and thus the less and less you require. This is what they call "slowing your metabolism," and in the process you lose lean muscle (you know, that highly metabolic tissue) because your body breaks it down to use the stored energy in it... because, well, your starving!

2. Pump Iron -- You want as much of this metabolically active tissue as possible and the one way to get more is by building more! Your muscle will require a higher number of calories each day to maintain a healthy body weight. Thus, the more muscle you have, the more calories you burn just sitting around. What you heard is true, you don't stop burning calories at the gym, you continue to burn on your way home and all through the next day.

3. Wet Your Whistle -- Always drink a glass of water as soon as you wake up, and throughout the day. Add a slice of lemon which not only adds some flavor, but the other benefit is the cleansing that it does to your liver, which helps to metabolize the food you eat. Plus, proper hydration has been associated with a more efficient metabolism.

4. Coffee Perks -- Go ahead, treat yourself to Starbucks--A study published in the American Journal of Clinical Nutrition showed that metabolic rate is raised for 3 hours after coffee intake, which may increase the rate at which body burns calories. Side note: if you don't already drink coffee, don't start! And, if you do, don't add sweeteners (even if they are calorie free!).

5. Make Time for Tea, Too -- Green tea is rich in antioxidants called catechins, which may trigger weight loss by stimulating the body to burn calories and decrease body fat. Buy tea bags in small amounts, though, and store in their original packaging, out of the sun: Studies have found that green tea bags can lose up to 32 percent of their antioxidant power in 6 months.

-- Terri MacLeod & Keri Glassman

Copyright 2012 by NBC Universal, Inc. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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