Stoking Your Metabolism, Eat More to Lose Weight
by Katherine E. Tallmadge, M.A., R.D.
Naomi, like many American women, is a wounded veteran of the diet wars
She had tried everything, especially if it promised quick results. The cleansing fast with nine days of lemon juice. The cabbage soup diet. The no-carbohydrate diet. Eating only fruits and vegetables. The diets would all “work” — she’d lose weight quickly, but the pounds had a way of coming back.
She would lose nine pounds in nine days, but gain back 15 in four days.
After a dozen years of yo-yo dieting, she wasn’t just getting nowhere, she was losing ground.
When she hit 200 pound she finally sought help from an expert and discovered the reason for her troubles. Because of her long-term serial dieting, her metabolism — the rate at which her body burns calories — had dropped by about 20 percent. This meant that, just to stay the same weight, she had to slash her caloric intake by 20 percent. To lose weight, she’d have to cut her consumption even more –and thereby risk slowing down her metabolism again.
She had been a severe calorie restrictor on and off for many years, and that stripped her body of muscle mass. Restrictive dieting and muscle mass loss are the main reasons why most people have low metabolisms.
This was Naomi’’s harsh introduction to the complex, sometimes baffling world of the human metabolism, which embeds one of the cruelest ironies in all of dietdom. Restricting calories — which is necessary to lose weight — can slow down the body’s metabolism, stunting one’s ability to burn calories, making weight loss virtually impossible.
Subjecting the body to repeated ‘famines’ causes a chronic dieter’s body to slow down into survival mod..
The less you eat, the more your body slows down, requiring you to eat even less. And when, out of frustration or exhaustion, you resume “normal” eating, your body grabs onto those extra calories and sends them into deep storage with a vengeance.
A growing body of scientific evidence confirms that the human body is an extraordinarily adaptive and delicate instrument whose instinctive drive for survival complicates the plans of even the most dedicated dieter. Henderson’s woes and those of others show clearly that losing weight and keeping it off require a careful understanding of the body and, specifically, its metabolic needs.
Each body’s calorie needs are largely determined by two factors: one’s level of physical activity and one’s resting metabolic rate (RMR).
About one third of the calories you burn are the result of physical activity, which includes anything other than resting–brushing your teeth, folding clothes, working at your computer, walking around the block, or exercising in your health club.
he other two-thirds are burned as a result of regular metabolic function. This includes the calories needed to sustain basic function: maintain body temperature, heart beat, breathing, organ repair and basic chemical reactions. Because RMR accounts for a large majority of calories burned, keeping your RMR high is essential to losing weight and keeping it off. In fact, it is more important to your weight-loss plan than is physical activity.
All of which raises the questions: How do you find out what your RMR is? And how can you raise it?
Your RMR is influenced by a variety of factors including genetics, body size, muscle mass, age, gender, body weight, pregnancy, hormonal status and, yes, physical condition. (More on this below, but the main point is that a fit and muscular body burns more calories while at rest than an unfit, less muscular one.) To make things more difficult, RMR naturally declines through adulthood at about 2 percent per decade, usually because of muscle loss. Chronic dieters exacerbate muscle loss through repeated quick weight reductions.
You can determine your RMR using Diet Simple’s Formula for Calculating Your Resting Metabolic Rate and Calorie Needs — free of charge and in the comfort of your own home and use that figure and a controlled diet to determine whether your RMR is lower than normal. First, determine what your RMR should be. Then continue the calculation to account for your level of physical activity and see how many calories you need to consume just to maintain your weight. Next, subtract 250 to 500 calories to determine a safe daily weight loss calorie level, which should produce a 1/2- to one-pound per-week weight loss.
Using the Diet Simple Formula, for a 150 pound, 5’4″ 40-year old lightly exercising woman, that would mean consuming about 1,978 calories per day to maintain weight and about 1,428 – 1,728 calories daily to lose weight. For a 200 pound, 6’1″ 50-year-old regularly exercising man, that would mean about 3,060 calories per day to maintain weight and about 2,560 to 2,810 calories daily to lose. (see examples)
Once you’ve done the math, spend at least one week –or up to a month — eating the calorie level you calculated should lead to a 1/2- to one-pound per-week weight loss. If you do not lose weight, and you’re sure you’ve calculated your calorie needs and your food intake correctly (cheating here will do you no good, folks), then that’s the sign your metabolism is probably low. This is an indication that you may benefit from visiting a clinic and getting tested to verify your metabolic status.
Using this equation is just a formalized way of discovering what many dieters do by trial and error. The dieter is eating what he or she believes is a weight-shedding calorie level, and documents it rigorously, yet the weight is not coming off.
If your metabolism is normal, in a way you’re lucky. Losing weight probably will require nothing more — to be fair, that probably should be “nothing less” — than consuming slightly fewer calories than you burn each day. Yes, it requires will power, and yes, it requires some exercise, but it can work, particularly if you run a modest daily caloric deficit (250 to 500 calories per day) and take the weight off slowly.
If, on the other hand, your metabolism is low, you might decide to meet with a doctor to find out why, and to learn what to do next. Your metabolism would be considered low enough to act on if it is six percent or lower than the equation predicts.
In addition to the repeated calorie restriction of yo-yo dieting, other factors that can contribute to lower metabolism include genetics and thyroid abnormalities. Thyroid levels can be tested in a physician’s office. It’s important to request a full thyroid work-up, including active thyroid (T-3), which isn’t usually tested, according to experts. If abnormal, it should be treated with medication. Once treated, a normal diet and exercise regimen should be able to take the weight off.
But a past of severe calorie restriction is the most common — and easily controllable — cause of a low RMR. And that requires a different plan of attack.
It doesn’t take a long history of dieting failures to affect metabolism. In fact, large increases or decreases in calorie intake for as little as several days can raise or lower RMR. Though for chronic dieters, because their bodies have been primed to go into survival mode — their metabolisms can lower in just 24 to 48 hours, according to experts.
It is widely accepted that, in response to starving, the body reduces levels of various hormones and chemicals that help determine metabolic rate: insulin, active thyroid hormone, norepinephrine (similar to adrenaline). This is a powerful survival mechanism, as it permits the body to slow the nervous, cardiovascular, and gastrointestinal systems to help it conserve resources of energy and calories during a period of assumed scarcity of food.
The groups most likely to have provoked their bodies into below normal metabolism are long term, yo-yo dieters; dieters who restrict their calories too severely; and people with eating disorders such as bulimia and anorexia nervosa, who either starve or alternate starving with binging.
The change in metabolic rate as a result of food restriction may vary from person to person. Studies show if a 200 pound woman is limited to 800 calories a day, after three weeks her metabolism may decline by 15 percent — possibly prompting further, unrealistic calorie reductions which cannot be sustained. Remarkably, exercise may actually exacerbate the problem. If a person isn’t consuming enough calories and is exercising,the body — which automatically does the math and reacts to an even more severe calorie deficit — will reduce its metabolism further.
Most people are told to eat less and exercise more, and it may not work for every person.
A low RMR has other consequences. The decline in metabolism makes it almost impossible to maintain weight loss. For example, if the metabolism for a 150-pound woman is just 6 percent below normal, that means she must eat 100 fewer calories per day to avoid weight gain. If it drops to 25 percent below normal, she must reduce daily consumption by 400 calories to stay even. This is a huge food deficit that few can maintain over a life time and contributes to the long term failure rates of diets, according to the experts.
So the dilemma is this: If restricting calories lowers the metabolism, endangering health and making weight loss and weight maintenance nearly impossible, how can weight loss be accomplished without wrecking the RMR? The answer, at the risk of appearing flip: Very carefully.
Experts agree that if the calorie restriction is minimal, the weight loss slow, and a cardiovascular exercise and muscle building program initiated, weight loss can be achieved safely and effectively, and a low metabolism can be reversed.
THREE ESSENTIAL ELEMENTS
Three factors are crucial for losing weight, maintaining it and keeping metabolism high.
First, since metabolism is dependent on lean body mass, muscle-building is an important type of exercise, regardless of whether your metabolism is high or low. The more lean muscle you have, the more calories your body burns. And since muscle mass naturally declines as you age, building muscle as you age is essential to keeping lean. In fact, as you become stronger and use heavier weights in your workout — an indication that you’ve gained muscle — you can eat more food because your need for calories naturally increases with muscle gain.
An average woman will lose five to seven pounds of muscle between age 35 to age 50 due to disuse. Add restrictive dieting to the equation, and even more muscle can be lost. For every pound of muscle lost, you lose the capacity to burn 35 to 50 calories per day. That means if you’ve lost seven pounds of muscle at 50 calories per muscle, that’s 350 calories you can’t eat just to prevent weight gain, let alone lose weight.
The American College of Sports Medicine recommends strength training all of your major muscle groups twice a week.
Second, cardiovascular activity burns body fat and calories (and, of course, improves your heart and general health). As you improve cardiovascularly, your body becomes more efficient and burns more fat with each exercise bout. A fit body also continues to burn more calories even after the workout has ended. The recommendation by most health groups is to accumulate at least 30 minutes per day of cardiovascular activity for health and weight maintenance. You may need to exercise more to lose weight, according to metabolic experts. I recommend all my clients wear pedometers to determine their overall activity level daily. I have found, likeit or not, 10,000 steps per day maintains health and weight. But if you want to lose weight, 12,000 steps or more is necessary.
The final element is diet. If you want to lose weight without affecting your metabolism negatively, the key is keeping calories as high as possible — but still slightly lower than what is needed to maintain weight. The metabolic experts recommend a daily caloric deficit of no more than 250 to 500 calories below the calorie level necessary to maintain your weight. Using the formula that 3,500 calories equals one pound, a daily deficit of 250 to 500 calories would produce losses of 1/2 – to one- pound every week. To prevent lowering metabolism, it’s important not to cut calories more than 500 per day under what would be needed for maintenance.
A study published in the American Journal of Clinical Nutrition, showed exercising women who lost 20 pounds in about 4 months — a slow rate compared with most diets — experienced no decrease in metabolism.
Studies confirm that weight losses on very low calorie diets produce reductions in RMR. And the thinking among weight loss researchers for years has been that this lowering of RMR during weight losses could not be prevented. They asserted that once a person lost weight, he would have to live with a metabolism which is lower than his same weight counterparts who never had to lose weight.
But metabolic experts today disagree with these long-held beliefs. They say these studies, conducted at some of the nation’s most prestigious institutions, were all done with very low calorie diets or modified fasts (such as the Optifast program), and this is the reason metabolisms dropped. The drop in RMR is not inevitable, they argue, if the weight is lost slowly, and calories are not restricted drastically.
So, don’t starve! If you eat the amount of calories necessary to sustain your metabolism, RMR does not decrease during weight loss. The key is avoiding starvation diets, and building and maintaining lean body mass through cardiovascular and resistance exercise.
If you’re starting with a low RMR, chances are you are eating too little. Once you raise your daily calorie intake using the recommended method, your metabolism will begin to rise. Your body will begin to reverse the negative physiological consequences of semi-starvation. In response to more food, the blood insulin level increases, hormone levels improve, the nervous, cardiovascular and gastrointestinal systems begin functioning up to speed.
But this process takes time, and you may maintain or even gain a few pounds at first. Normalizing metabolism, which is necessary before permanent weight loss can take place, may take several months for a chronic dieter. For an anorexic, it may take years. It depends on the severity of the problem. And, at first, you may experience an increase in weight, due mostly to increased water gain, but also because it takes time for the metabolism to reverse. An increase in water weight may occur once normal eating is resumed after starving. That’s one reason weight seems to rush back on as soon as normal eating is resumed after a restrictive diet. One way to reduce this discouraging, but expected, water gain is to keep carbohydrate intake lower than normal during the calorie-increasing process, as carbohydrates attract water and may increase water weight if you’ve been starving. (One reason a low carbohydrate diet seems to work so well is it causes water loss!)
Simply increase calories incrementally to reduce sudden weight gain. This gives the metabolism time to adjust to the new calorie levels and minimizes water gain. For instance, add an extra 100 calories every week or every two weeks,
Naomi’s RMR was low due to chronic dieting coupled with a lack of exercise. It was markedly improved in about four months via exercise – and calorie restriction only slightly below what her body required. It took two years to lose the unwanted 20 pounds and bring the metabolism completely back to normal. And because Naomi built so much muscle, her size changed more that the pounds on the scale reflected. She proudly proclaims she went from a size 18 to a size 12.
She first had to build up the muscle and then use the muscle to burn the excess fat on her body. The secret to a high metabolism and weight control is to combine aerobic activity and weight training.
But Naomi’s diet needed a makeover too. When she was gaining weight, she was eating a high starch and fat diet, with most of the calories eaten in the evenings.
She rearranged her diet, reflecting the U.S. Dietary Guidelines (15 to 20 percent protein; 20 to 30 percent fat, 50 to 55 percent carbohydrates). She added more protein, fruits and vegetables and reduced fat and starches. Her nutrition program started with about 1600 calories But as she gained muscle and normalized her metabolism, she was able to add 100 more and continue to lose weight — a veritable feast compared to the depressingly restrictive diets she was used to.
She began spreading her calories more evenly through the day (a key principle in Diet Simple). Other metabolic experts agree this is an important step for a variety of reasons. Evidence suggests a pattern of eating three large meals per day, including planned mid-morning and afternoon snacks, if desired, increases metabolism slightly. After eating, food stimulates an increase in the metabolism. So increasing the number of meals eaten starting in the morning takes the best advantage of this phenomenon, called the “thermic effect of food.” (Protein and carbohydrate have a higher thermic effect than fat.)
People who skip breakfast or lunch may have lower metabolisms. But, most importantly, eating a breakfast, lunch, and dinner of equal size decreases food cravings and overeating in the evenings — a cardinal sin, according to metabolism experts. Other evidence suggests people who eat heavily in the evenings are heavier than those who eat the same calories spread throughout the day.
Understanding the importance of spreading out her meals and spending time taking care of herself with regular physical activity were important breakthroughs. When coupled with an understanding of her metabolism, this has allowed her to live a more vigorous and slender life.
Most importantly, with a calorie level that is satisfying and a well-trained body, your results are more likely to endure over a life time.
Diet Simple’s Formula for Calculating Your Resting Metabolic Rate and Calorie Needs*
(for people over 17 years old)
1. Begin with a base of 655 calories 655_______
2. Multiply your weight in pounds X 4.3 __________
3. Multiply your height in inches X 4.7 __________
4. Add together the totals from #1, #2, and #3 ___________
5. Multiply your age X 4.7 ___________
6. Subtract result of #5 from total of #4 ___________ (your normal RMR)
7. Multiply #6 by your activity factor**___________ (your daily maintenance calories)
8. Subtract 250 calories ________ (your daily weight loss calories)
**For most of my client, I use 1.3 as their activity factor and it seems to be correct.
1. Begin with a base of 66 calories 66______
2. Multiply your weight in pounds X 6.3 ________
3. Multiply your height in inches X 12.7 ________
4. Add together the totals from #1, #2, and #3 ________
5. Multiply your age X 6.8 ________
6. Subtract result of #5 from total of #4 ________ (your normal RMR)
7. Multiply #6 by your activity factor** _______ (your daily maintenance calories)
8. Subtract 250 – 500 calories ________ (your weight loss level)
**For most of my client, I use 1.3 as their activity factor and it seems to work for most of us desk jockeys…
For activity, multiply:
RMR times 1.2 for extremely low levels of activity (sedentary)
RMR times 1.3 for light physical activity (2 – 4 hours/week)
RMR times 1.4 for moderate physical activity (4 – 7 hours/week), and
RMR times 1.6 for high levels of activity (regular exercise or manual labor)
Some athletes may double or even triple their RMR to determine their daily calorie needs
*Based on the Harris Benedict Equation
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