Dr. Arthur Agatston first introduced "The South Beach Diet" five years ago, and it became a popular way to lose weight. Now, he's following up with a new book that offers a way to change your lifestyle for increased weight-loss success. Here's an excerpt.
Supercharge Your Metabolism
My patient Susan, who was prediabetic, had lost more than 20 pounds on the South Beach Diet. Although she looked and felt a lot better, she wasn’t happy. She still wanted to lose another 5 to 10 pounds but was having difficulty doing so. No matter what she did, she couldn’t seem to lose more weight. She asked me, “Couldn’t I just go back to Phase 1? I had no trouble losing weight back then!”
I strongly advised against it. Phase 1 is designed for people with cravings and substantial weight to lose, not for someone like Susan, who had only a few pounds left to shed. More important, Susan’s cravings were gone, and her blood chemistries were normal. In cases like hers, cutting back on calories and once again limiting nutritious food choices like fruits and whole grains could be counterproductive and potentially lead to yo-yoing (see page 41).
If Susan wanted further safe weight loss while continuing to follow the healthy eating principles of the South Beach Diet, she had only one option: She had to burn more calories. And the most efficient way to accomplish this was by engaging in the most efficient form of regular exercise. That meant more or better exercise, and that was exactly what Susan didn’t want to hear. She was already getting up at 6:00 a.m. to spend, as she put it, “one long, tedious hour” walking on her treadmill before getting her kids off to school and going to work.
“Don’t tell me I have to spend more time on the treadmill,” Susan complained. “I just can’t get up any earlier!”
Susan was pleasantly surprised when I explained that she didn’t have to spend more time exercising to burn more calories. She could actually jump-start her metabolism and burn more calories in less time by making some changes in her exercise routine.
I told Susan that doing more of the same wasn’t going to work. Her body had become accustomed to operating at her new weight and her current activity level, as often happens after a period of successful dieting. In fact, the most common complaint of dieters is what they call hitting a plateau. I’m sure many of you have experienced it.
Depending on our intrinsic metabolism, we all have different set points where our weight will plateau, even though we may be doing exactly the same thing we’ve been doing all along to lose weight. There are, of course, those lucky people who are born with a naturally high metabolic rate and who never have to diet or worry about hitting -plateaus—they’re the people we all love to hate because they seem to be able to eat anything and not gain weight. It simply doesn’t seem fair!
Susan, like most of us, wasn’t so lucky. Her problem was that her metabolism was stuck in neutral. Her body had adjusted to her need for fewer calories, so she was neither gaining nor losing.
Her only healthy and sustainable solution was to change her exercise routine and shift her metabolism into a higher gear. In other words, since Susan did not inherit a fast metabolism, she would have to rev it up — herself.
Do More with Less
I advised Susan to switch to an interval training program. In interval training, you alternate between short bursts of intensive effort and easier recovery periods, as opposed to working at a steady, continuous, and potentially monotonous pace. While this book focuses on walking, just about any form of exercise can be done in an interval training mode, including swimming, running, biking, elliptical training, and even strength training.
Here’s the advantage: When you work at a higher intensity for part of the time, you end up burning far more calories and fat in less time than you would if you were working out at a steady pace. And there’s a bonus: With interval training, the higher the intensity of the exercise, the longer the afterburn; that is, you will continue to burn more fat and calories after you’ve completed your exercise session. As you become more fit and develop more lean muscle mass, you increase your basal metabolic rate even further. This means you’ll burn more fat and calories while you’re going through your daily activities, and even while you’re resting.
Don’t let the term higher intensity scare you. It’s true that you may be working harder than you’re used to for short periods of time, but you will have plenty of time to recharge during the easier recovery periods. Interval training is not just for the very fit. It works just as well for people who are not as fit and is even being used to help cardiac patients and people with lung disease get back in shape. That said, I do recommend that you talk with your doctor before embarking on this or any exercise program, especially if you haven’t been exercising.
Susan was also missing another important component of fitness—a core-strengthening program to develop the muscles in her back and abdomen and increase her overall strength and flexibility. Susan’s treadmill workout focused on her cardiovascular system, but she needed to do something more to further improve her muscle tone and bone density.
Due to a natural decrease in hormones and to reduced physical activity, both men and women tend to lose muscle and bone as they age. For women, this drop in hormones occurs fairly abruptly during menopause and typically causes a drop in metabolic rate. Consequently, postmenopausal women invariably find it much tougher to maintain their weight.
For men, the drop in hormones—what is called andropause—is more gradual, but it too results in a slower metabolism and weight gain with age.
In both men and women, decreased hormone levels and decreased physical activity also diminish the quantity of muscle (and bone). Since muscle requires more calories to maintain than fat, less muscle means fewer calories burned, which further slows metabolism. By maintaining your muscle mass with exercise, you can help overcome the natural decrease in metabolic rate.
That’s why, as you age, it’s so important to keep your metabolism revved up. If you want those muscles to be metabolically active—if you want to burn more fat and calories—you must use them. I therefore recommended that Susan follow the South Beach Supercharged Fitness Program, described in Part II. Before she could protest that she was already pressed for time, I showed her how she could do an even more effective cardio and calorie-burning program in half the time she was already spending on the treadmill (and achieve core fitness and greater overall muscle tone on alternate days).
The Pounds Melted Away
Here’s how we transformed Susan’s 1-hour treadmill program into a fat—busting, calorie-devouring interval training program. I instructed Susan to cut her treadmill time back to about 20 minutes every other day. Instead of walking at a constant pace for her entire workout, as she had been doing, she should mix it up. That is, after a warmup, she should alternate short bursts of walking very fast with recovery periods of slower walking. (See page 109 to get started on Phase 1 Interval Walking.)
Depending on the workout goal for the day, Susan could do several fast-slow intervals within 20 minutes. As her endurance improved, she would be able to spend more time doing fast spurts and less time in the slower recovery periods, gradually adding more repetitions if time permitted. In addition, she wouldn’t be bored: When you do interval training, your workouts vary so they’re more interesting, and the time seems to fly by.
Another benefit of the program was that on alternate days, Susan would strengthen her core muscles, which she had been neglecting by doing only cardio.
Susan was skeptical but agreed to give it a try.
When I saw Susan about a month later, I didn’t have to ask how she was doing. I could see the good results with my own eyes. Those last 10 unwanted pounds were fading away. And, thanks to the core component of the program, Susan was standing straighter and looking stronger and better toned.
The Conventional Wisdom Is Wrong
At this point, many of you may be thinking, This contradicts nearly everything I’ve been told about exercise. And you’re right, it does. In the past, we believed that the best way to burn fat was to work at your training heart rate, which is about 60 percent of your maximum heart rate. Once you knew your training heart rate, you were told to take your pulse or wear a heart-rate monitor during exercise to make sure you maintained that level. You were also told that you needed to work for at least 20 minutes before you started burning fat. We now know that this simply is not true.
Interval training is not new. Endurance athletes like marathoners and professional cyclists have used this technique for years to help them perform at higher levels. But now there is growing evidence that interval training can also be a huge boon to nonathletes who are trying to lose weight and improve their fitness. An abundance of good science supports interval training as a great way to burn fat and calories, and research also shows that it provides better results than working at a constant moderate pace for longer periods of time.
In a 2007 study conducted at the University of Guelph in Ontario, researchers had women in their early twenties do an interval training program consisting of 10 sets of 4 minutes of hard cycling with 2 minutes of rest between each set. After seven 1-hour sessions over 2 weeks, all eight women in the study showed a 36 percent increase in fat burning. This finding held true for women who were fit, as well as for those who were less fit. So much for the myth that you can’t burn fat working at a high intensity! The women also showed a 13 percent improvement in cardiovascular fitness, which means their hearts and lungs were better able to send oxygen to working muscles, which is important whether you are working out or simply going about your daily activities.
Burning calories is critical to shedding pounds and maintaining a healthy weight. And on the calorie-burning front, interval training is the clear winner. A landmark study conducted by Darlene Sedlock, PhD, and her colleagues at Purdue University found that it took only 19 minutes for a high-intensity exercise group to burn the same 300 calories that it took a low-intensity group 30 minutes to burn. Even more interesting, the high-intensity group continued to burn more calories long after the exercise period ended, compared with the low-intensity group.
In another study, conducted jointly by Baylor University and the University of Alabama, researchers compared continuous low-intensity exercise performed for 60 minutes to a high-intensity interval training program alternating between 2-minute periods of work and recovery, also for 60 minutes. The participants were eight women between ages 23 and 35. Researchers found that the interval training protocol burned 160 more calories per day than the low-intensity training method, or about 800 calories more per week when the exercises were performed five times a week.
The point is that if you want to burn more calories, you need to work out with greater intensity. But don’t worry, we’re not telling you this so you feel compelled to get on the treadmill for an hour a day. In fact, we’ve already seen some excellent results with women we’ve put on our 20-minute-a-day Interval Walking program. Not only have they lost excess pounds, but they’ve lost them in trouble spots like the waist and hips.
Studies also reveal that interval training is more effective for normalizing blood sugar and correcting bad blood fats (such as LDL, or low-density lipoprotein, cholesterol, and high triglycerides) than conventional exercise, making it ideal for cardiovascular health. This means that interval training is a wonderful choice for people at risk of developing prediabetes and diabetes. And it’s particularly effective for burning away belly fat, the dangerous visceral fat that is the bane of many men and women in midlife.
There’s yet another reason interval training is preferable to conventional training: It prepares you better for living in the real world. Consider this. Do you take your training heart rate when you leave the house in the morning and stay at that level for the whole day? Of course not. You’re constantly speeding up and slowing down as you go about your activities, whether you’re getting up from a desk, running for a bus, or chasing after a toddler. Our lives are actually built around interval activities. Therefore, an ideal fitness program should prepare you for the kinds of physical demands you encounter every day. And interval training does just that.
How Interval Training Works
How does interval training work? It switches your metabolism into high gear and increases your demand for energy (calories) so that you burn more calories and fat. Think of your body as a car. When you drive in stop-and-go traffic, you burn a lot more gas than when cruising along at a constant speed. With gas prices so high these days (let alone our desire to use less fossil fuel), that’s the last thing you want to do when you’re driving. But it’s exactly what you do want to do to burn maximum calories and fat during exercise. And that’s how interval training works. Every time you work hard and then slow down, you waste energy and use up calories. And what it’s costing you are those extra, unwanted pounds.
As good as it is, intense interval training isn’t for everyone. It must be customized for people with certain orthopedic problems or serious heart conditions. Again, my advice is to check with your physician before starting this or any other exercise program.
Excerpted from "The South Beach Diet Supercharged: Faster Weight Loss and Better Health for Life" by Arthur Agatston, M.D. Copyright 2008 Arthur Agatston. Reprinted with permission from Rodale Books. All rights reserved. For more information, visit www.southbeachdiet.com.