On Nutrition by Ed Blonz

AGE-RELATED WEIGHT GAIN IS EXPECTED, BUT NOT INEVITABLE

DEAR DR. BLONZ: I eat well and exercise regularly, but despite these good habits, I have noticed weight gain around my middle. It's very bothersome to me. Is this just part of getting old? I can't improve my diet much more, and am frustrated at this bulge. Nothing has really changed except the shape of my body. -- S.S., San Dimas, California

DEAR S.S.: There is a natural decline in the amount of energy (calories) the body requires as the years go by. Couple this with the typical decrease in activity as we age, and it's easy to understand the impact on the shape of our bodies. The slowdown in calorie burning is gradual, and it represents a problem for those who continue to ingest the same daily calories that they always have, or even more.

The body needs energy to operate, and there are three basic categories of body energy. First and foremost is the resting metabolic rate (RMR). These calories represent the energy needed to keep the body ticking. This is our caloric "cost of living," and it represents about 60 to 75 percent of our daily caloric requirement. Next is the energy used for activity, which amounts to about 15 to 30 percent of the caloric requirement for the average individual. Finally we have the thermic effect of food (TEF), which is the energy burned as a direct result of eating. It represents about 5 to 10 percent of daily calories. Weight tends to remains stable as long as we consume the number of calories our body requires.

An older body, however, will burn fewer calories than a comparable younger body, even if both ate the same and had the same level of physical activity. A study in the February 2005 issue of the European Journal of Clinical Nutrition reported that the decline associated with aging is not solely a function of the fact that we tend to lose lean body mass (muscle, organ weight and bone) as we age.

No question, it is best to remain active, as this will help slow down the slowdown. Staying active not only burns the calories associated with the activity, it also helps maintain your muscle mass. Muscle is active tissue, and similar to the way an eight-cylinder car burns more gas at idle than a four-cylinder car, having more muscle mass burns additional calories even when you are at rest. Studies in the February 2006 Journal of Physiology and the August 2007 Journal of Applied Physiology provide independent confirmation how the TEF component of our daily calorie requirement is greater in those with regular exercise habits.

If you will allow a personal observation, I noticed a couple of years ago that there was -- slowly but surely -- getting to be a bit more of me. So I added 15 minutes of aerobic time to my three-times-a-week exercise sessions and that helped me to regain control of the trend.

We all need to keep up with our activities and find a way to make exercise a fixed part of our routine. There should be an aerobic element as well as resistance exercises. If you have health issues, you can touch base with your physician. If you have any physical limitations or concerns, consider speaking with a certified trainer at a gym to develop a personalized program.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.