OBTAIN OPTIMAL NUTRITION - Printer Friendly

OBTAIN OPTIMAL NUTRITION

Answers to your frequently asked questions on eating for fitness.

Written by Bonnie Modugno, M.S., R.D.

A Better Time to Burn?
Q. I'd like to lose about 10 pounds. When is the best time for me to work out to burn more bodyfat?
A. This question was recently discussed at the annual meeting of the American College of Sports Medicine in Indianapolis. It's fairly well understood that after resistance training, the body burns relatively more fat during a cardiovascular workout. Hence, many trainers encourage individuals to walk, run or ride a bike after weight training.

What isn't as well known is that this blip in fat metabolism is an acute, short-term effect. Studies looking at 24-hour energy utilization show no real difference in overall fat utilization over the entire day. For this reason, it probably doesn't matter when you exercise, except to do it when you can, when you want to and, most important, when you'll enjoy it.

Metabolism Madness
Q. Over the years I've added more exercise to my training regimen and am eating less than ever (about 1,500 calories a day). I just seem to maintain, not lose any more weight. What's going on?
A. You may actually be training your body to be more efficient, thus allowing your metabolism to adjust to fewer calories and a higher energy output. According to endocrinologist C. Wayne Calloway, MD, former director of the Center for Clinical Nutrition at George Washington University Medical Center, now in private practice in Washington, D.C., observations in anorexic young women link their dieting and exercise regimens with resting metabolic rates that are more than 50% lower than expected. This is a lower metabolic rate than can be explained by the loss of muscle mass alone.

In addition, studies have shown that women on very-low-calorie diets (800 calories per day) who exercised actually suffered a greater slowdown of resting energy expenditure (60% of prediet measures) than women who dieted more moderately without exercise. Perhaps 1,500 calories a day intake coupled with 2-3 hours of activity daily triggers a similar training effect to make your metabolism very efficient and thus burn fewer calories. At any rate, continuing to try to control your weight with increasingly restrictive diets will only make matters worse.

What can you do? One or a combination of factors may help, including the following:
1. Slowly increase--yes, increase--your food intake to encourage a faster metabolic rate.

2. Increase your protein intake to avoid eating a carbohydrate-rich meal or more carbs than you're used to. That causes rapid weight gain due to bloating when insulin levels surge.

3. Increase your lean body mass--here's where resistance training comes in--to increase your metabolic rate. Yet do so carefully, since too much exercise with inadequate calories can make the efficiency more intense.

4. Eat several small meals throughout the day, choosing a variety of foods and including some healthy fat in your diet.

Index Information
Q. How effective is eating only low-glycemic-index carbohydrate foods?
A. Typically, foods that are considered low-glycemic are whole foods: grains, vegetables and fruits. They're great sources of carbohydrate and contribute plenty of vitamins, minerals and other phytochemicals along with their energy value.

If you're looking for energy foods that are nutrient-dense and likely to be metabolized with less influence on insulin levels, whole foods work well. If you want sources of quick energy in the middle of a workout, a refined glucose electrolyte beverage or other high-glycemic carbohydrate may be more practical. And if you train intensely and find that eating only whole foods provides such a bulky diet that it's difficult to maintain adequate glycogen stores for energy, you may need to consume some of both carbohydrate sources.

Beat the Bloat
Q. No matter how hard I train or how carefully I eat, I end up feeling bloated and lethargic the week before my period. Am I doing something wrong?
A. You could be, if you're eating a lot of carbohydrates at that time. Research by Mark Tarnopolsky, MD, PhD, associate professor in the department of medicine and kinesiology at McMaster University Medical Center, Ontario, Canada, has demonstrated a shift in energy metabolism between the follicular phase (the two weeks before ovulation) and the luteal phase (the two weeks after ovulation) of the menstrual cycle.

Women seem to metabolize carbohydrate more effectively during the follicular phase and less effectively after ovulation until they start their period, which is the onset of the new follicular phase. Ironically, just at the time we traditionally crave carb foods, we may be better off with less carbohydrate and more protein and/or fat in our diets. You'll know after a few months if a lower ratio of carbohydrate to protein/fat helps you experience less bloating, have more energy and crave sugar less (but you'll still crave it somewhat) during that last week or so before your period.

Carbs While Training
Q. How important are carbohydrate supplements, like sports drinks, during training?
A. In a nutshell, it depends on your goals. If you're training for a competitive advantage, carb supplements may help you train harder and longer and can be an important key to energy management, especially if you train longer than 90 minutes per session or multiple times a day.

If you train with less intensity, carbohydrate supplements probably aren't warranted unless you're exercising for more than 90 minutes at a time.

Doing the Math
Q. I train hard and I know I need carbohydrates. How much is enough?
A. Typical recommendations for adequate carbohydrate intake while training can be stated in different ways. The most general recommendations suggest 60%-70% of your daily calorie intake come from carbs. Another general guideline suggests at least 350 grams of carbohydrate per day. More specific recommendations stipulate 4-5 grams of carbohydrate per kilogram of bodyweight (or about 1.8-2.3 grams per pound).

When you do the math with the different formulas, you get pretty different answers. The first formula based on calorie intake is highly variable: If you eat 2,000 calories per day, the recommendations would lead to 300-350 grams per day. If you train hard, you may eat 3,000 or more calories a day, and that 60%-70% carbohydrate ratio translates to 450-525 grams daily.

The last equation is based on the athlete's total weight. Remembering that 1 kilogram is equivalent to 2.2 pounds, a 150-pound woman (about 68 kilograms) would need to consume 282-340 grams of carbohydrate per day. But a 110-pound woman would be guided to consume 200-250 grams per day. As you can see, variations in weight lead to significantly different numbers. In addition, based on recent research, I'm not so sure all female athletes handle this amount of carbohydrate successfully.

While most conventional research regarding fuel intake and glycogen stores was done exclusively on young athletic males, research by Tarnopolsky in 1990 showed that in the same bout of exercise (90 minutes at 63% VO2 max, a measure of how much oxygen the body uses), women burned 42% of calories from fat (428 calories) compared to men burning only 19% (242 calories). Women were studied in mid-follicular phase, with great detail paid to the selection of subjects for greater experimental control.

We don't know all the answers here, but perhaps women just don't need as much carbohydrate to adequately replenish glycogen stores. You may want to start out with the higher intakes recommended in the traditional formulas, but if you feel bloated or lethargic or gain weight, experiment with fewer carbs and more protein and fat until you find an appropriate balance.

What's Overweight, Really?
Q. I'm considered overweight by the BMI (body mass index) standards, but I'm only 14% bodyfat. What are they talking about?
A. BMI is basically a finite calculation of bodyweight measured in kilograms divided by height measured in meters and then squared. Researchers and statisticians love this neat number to identify the population in terms of overweight and obesity as these data relate to health risks. The problem is that no adjustment is made for body composition (your percentage of bodyfat to lean mass).

Most of us working with athletes know that as soon as someone accumulates significant muscle mass, it's all too easy to reach higher BMI levels and thus be considered overweight, even obese. This is ridiculous, but the BMI standards offer no insight to the question of fitness.

Many researchers and clinicians are coming to agree with findings by Jean Pierre Despres, PhD, director of the Lipid Research Center at Laval University Medical Research Center, Ste. Foy, Quebec, Canada. His position is that waist circumference may be a far more definitive marker of health risk than weight and height comparisons like the BMI, and possibly even more meaningful than bodyfat composition measures.

Too Much Protein?
Q. Is there a risk of eating too much protein? I keep hearing warnings about osteoporosis and kidney damage.
A. I'm amused that the scientific community continues to wave a flag of fear regarding protein intake when no data support such threats. Evidence indicates that humans have eaten far more protein over the ages without deleterious effects.

Mary Gannon, PhD, director of the Metabolic Research Laboratory, associate professor of food science and nutrition and associate professor of medicine at the University of Minnesota in Minneapolis, shared anthropological data regarding protein intake of various populations consuming 300-400 grams of protein a day without harm.

In addition, the only study linking kidney damage with protein intake involved subjects already suffering from renal failure. Finally, osteoporosis has merely been linked with a high-protein diet in an epidemiological study. This isn't a cause-and-effect finding and deserves to be looked at more closely before scaring the masses off protein.

Weight-Loss Woes
Q. I lose weight readily when I diet, but as soon as I start to eat more of the same diet foods, I gain weight. I can't seem to find "maintenance." Can you help?
A. Many reasons could explain this phenomenon. You may need to experiment to find out what exactly your body is reacting to. Possibly you eat so few calories in dieting that your body loses glycogen stores and water (3-4 pounds) or lean body mass (700 calories per pound) or both. When you eat more, your body will naturally replenish those glycogen stores and water--in as little as 24-36 hours. If you work out, your body will eventually regain muscle mass if there's enough energy support.

On another track, maybe you're eating few carbohydrates on that restricted intake, and when you eat more carbs than you can handle--even a little more--you may experience some bloating and immediate weight gain.

Lastly, if you spend a lot of time analyzing what and how much you should eat, you've probably learned to not pay attention to your body's signals of "enough." Practiced dieters often find themselves in a no-win situation, either dieting or overeating. Learn your body's natural cues for hunger and satiety so you'll avoid overdoing it when you go off your diet.