If this confuses you, don’t sweat it. Just remember that selecting a slower speed and lower intensity to maximize fat burning is counterproductive — unless it enables you to exercise longer and burn more calories. Whenever you exercise, try to work to the point where you feel warm and slightly out of breath. If you do, then you can be sure that you’re doing the best you can to burn lots of fat and glucose, increase your level of fitness, and improve your health.
Don’t lift weights if you’re trying to lose weight.
Some people don’t want to weight train while they’re on a weight-loss program because they know that building muscle might cause some weight gain. That’s true, because muscle tissue is heavier than fat, but muscle is exactly what you want to gain when you’re trying to lose weight. Here’s why: When you restrict calories to lose weight, you always lose some muscle. In fact, up to 25% of your body-weight loss can be from muscle. (So if you lose 10 pounds, 2.5 pounds of it could be muscle.) The problem with losing muscle during weight loss is that muscle is the engine that burns calories and helps maintain your metabolic rate. If you have less muscle, you reduce your ability to burn calories, lose more weight, and, more important, maintain your weight loss. (The plateau that many people experience during weight loss can be explained partially by loss of muscle.)
In most cases, moderate weight training will not amount to more than 3–5 pounds of weight gain anyway, but even if it did, it’s what you want, because each pound of muscle consumes about 35–50 calories a day. So next time someone drops by and offers you five pounds of muscle, go ahead and take it; it’ll help you use up an additional 175–250 calories daily.
Muscle is also the engine that burns glucose. The more muscle you have, the more glucose you can burn, and the better your diabetes control may be. So pour on the muscle. Lift weights all you want, whenever you want.
Exercise in the morning works better than exercise at night.
Some people believe that if you go to sleep right after exercise you won’t get as much benefit from the workout, because your metabolic rate slows down while you’re sleeping. If you exercise in the morning, they say, you jump-start your metabolism and burn more calories throughout the day. There’s no evidence that this is true.
Another reason some people believe morning exercise is superior to nighttime exercise is that exercising right before bed supposedly keeps you awake longer. Research shows that that may be true, but generally only for deconditioned people. For fit people, exercise before bedtime does not alter sleep patterns, probably because their bodies are used to and recover quickly from the effects of exercise. Some health experts suggest that regular exercise may even help improve sleep quality and sleep onset over time.
The bottom line is that the body responds to exercise whenever you do it. If exercising at night fits your schedule better, then by all means do it then. If getting a workout first thing in the morning makes you feel more energetic, all the better. The best time to exercise is the time you are most likely to do it.
Walking isn’t enough.
Walking may not be as arduous as training for a marathon, but when it comes to preventing diabetes, complications of diabetes, and heart disease, it’s powerful medicine. The Diabetes Prevention Program, a three-year, government-sponsored study designed to test the ability of healthy behavior changes to prevent diabetes, showed that when people under the age of 60 who had impaired glucose tolerance, or prediabetes (a condition that often precedes Type 2 diabetes), walked 150 minutes per week (that’s five 30-minute walks per week) and followed a low-fat diet (enabling them to lose 5% to 7% of their body weight), they reduced their risk of diabetes by 58%. For people over 60, the risk reduction was 71%.