Q: How can I benefit from a session with a regular dietitian, and how do I find a good one?
A: A registered dietitian (R.D.) can help you whether you need a few nutritional pointers or you want a complete diet overhaul. To be an R.D. one must have a college degree in dietetics, as well as clinical experience, and must be certified by the American Dietetic Association. Many R.D.s are well versed in sports nutrition, but they often also specialize in such areas as diabetes, weight loss, or heart health.
In one or more sessions with an R.D., you should be provided with eating plans and specific food guidelines tailored to your dietary needs. Some dietitians may even join you in the grocery store to teach you how to shop for optimal health.
To find a dietitian in your area, go to eatright.org. Call a few dietitians and discuss their rates (which can range from $75 to $250 per hour), as well as their views on eating, foods, and supplements. I suggest you avoid dietitians who push supplements over food. Also be wary of "food cops" who exclude food groups or pit good foods against bad foods.
Q: Neither my weight nor my diet nor my running habits have changed for 20 years—but my waist measurement has steadily grown. What gives?
A: Even runners who stay in top shape as they age may see their waistlines expand due to declining levels of "youth" hormones, such as growth hormone, which alter where body fat is stored as well as declining muscle mass. While your diet may not have changed much, certain foods can have a bigger impact on weight gain as you age. Keep your belt buckle in the same hole with these strategies:
Pack in produce. Studies show that people who eat ample fruits and vegetables have smaller waists than those who skimp on produce. Researchers theorize a diet rich in fruits and veggies helps curb blood-sugar swings, which can influence the hormones that make fat.
Keep it whole. Eating whole-grain over refined-grain products keeps waistlines trim. Research reveals refined-grain eaters have larger waists, which may be related to a lower fiber intake and its impact on controlling body fat.
Easy on the alcohol. Studies show heavy alcohol consumption leads to fat accumulation around the middle. Women should drink no more than one drink daily, and men should limit themselves to two drinks per day.
Stay fit. Studies show people lose specifically from their waist when exercise is part of their weight-loss program. Upping your mileage or occasionally adding other cross-training workouts may help shave off inches.
Q: What's the best race distance to train for to lose weight?
A: Many runners assume marathon training is the fastest way to lose weight, because all those extra miles add up to lots of burned calories. But the additional miles will also increase appetite, leading some runners to eat too many calories to lose weight.
So rather than running longer, I suggest concentrating on pace. Specifically, try speeding up on one to three of your runs per week (alternating your faster days with easy days). Running faster burns more calories and helps you lose weight in three ways.
(1) You burn about 100 calories for every mile you run. But as intensity increases, so does calorie burning—up to 10 calories per minute per mile. That may sound like a small difference, but it adds up.
(2) After a run, you burn additional calories as your body recovers. The harder you run, the more energy you'll expend post-exercise. One study showed that a high-effort exercise session boosted the "afterburn" by more than double compared with a low-effort session.
(3) High-intensity running puts a damper on your appetite. After a longer, slower jog you may well be hungry, while after a hard run, you usually don't feel like eating. Researchers theorize that a high-intensity effort heats up the body more, which affects temperature-sensitive appetite controls in the central nervous system.
Q: I've heard that running on an empty stomach will help me burn more fat. True?
A: Running on an empty stomach does increase the amount of fat calories burned. But this doesn't mean faster weight loss. When running, you burn both carbs and fat. If you're low on carbs, the body will kick in more stored fats for fuel. But due to low energy, you may not run as hard or as long. And after your run, your metabolism may slow due to your semifasted state. All this translates into fewer total calories burned. So eat a snack. You'll run better and burn more calories than if you were running on empty.
—Liz Applegate, Ph.D., is the director of sports nutrition and nutrition department faculty member at the University of California at Davis in Davis, California.
Q: To lose weight, am I better off running lots of slow miles, or fewer but faster miles?
A: The simple answer is that running at any speed expends approximately 100 calories per mile. Running a seven-minute mile will burn a few more calories than running a 10-minute mile because of the added effort. But most people can't log lots of additional miles at a faster pace without becoming overly fatigued or injured. So you're likely to accumulate more miles—and burn more calories—over the course of each week by running at a slower pace.
To lose weight, your energy expenditure (moving and exercising) must exceed your energy intake (eating and drinking). You can do this by eating less, exercising more, or a combination of both. Plenty of slower miles can help create a steady calorie deficit that will lead to weight loss.
—Bryan K. Smith, Ph.D., is an assistant research professor at the University of Kansas Energy Balance Laboratory and Center for Physical Activity & Weight Management.
Q: Will losing five pounds help me shave a few minutes off my half-marathon PR?
A: For every pound you lose, you'll run about two seconds faster per mile. So losing five could cut two minutes off your time. But if you're already slim, dropping more pounds could lead to muscle loss. Even if you have weight to lose, slashing calories will affect your energy and increase your injury risk. To safely slim down, lose one half to one pound per week by making small changes: Eat fiber-rich foods (like sweet potatoes or beans), which fill you up. Trim calories by skipping snacks when you're not hungry, drinking less alcohol, and eating fewer desserts.
—Lisa Dorfman, R.D., is the Director of Sports Nutrition and Performance-UHealth at the University of Miami.
