By DiAnn Lanke Stasik 01/10/04
“Caveat emptor” is the Latin phrase for “buyer beware”. This is true of products and services. One type of product that necessitates caution is a diet book. As a personal trainer and group fitness instructor I have lately received a lot of questions pertaining to high protein/low carbohydrate diets from patients, clients and students. Most people that ask if they should try this or that diet and are looking for a quick “yes” or “no” answer. Generally, they don’t have the time to listen to an in depth explanation to my canned response of “Not healthy, not good – unless your doctor has a valid medical basis for putting you on such a restrictive diet.” So for those of you who can make the time to read more of an explanation I will provide a brief summary of exercise physiology – the function of the body as it responds to exercise. Be prepared to learn some new terms because I’m going to get technical on you. You may also want to grab a calculator for the equation I will provide you at the end of this article.
Let’s address the fundamentals of nutrition and anatomy. First, there are only six essential nutrients that your body needs. They are: carbohydrate, protein, fat, water, vitamins and minerals. Second, your body weight is comprised of
60 – 65 % water. Third, the components of skeletal muscle are as follows: 75% water, 20% protein, and 5% electrolytes. Because high protein/low carbohydrate diets are the latest “fad” and are generally based on the reduction of carbohydrate and opponents repute that weight loss from these diets are from water loss, I will elaborate on carbohydrate and water.
When a carbohydrate is digested, it is broken down into glucose for your body to use. Carbohydrate is then stored in your liver and skeletal muscles as glycogen. Your body will access glucose/glycogen through the three energy systems that it has: (1) the ATP-PC System (a.k.a. Phosphagen), (2) the Anaerobic Glycolysis System and (3) the Aerobic System. Each system is not exclusive; our bodies always used them in some combination. The ATP-PC System is the only system that does not require glucose as a fuel source. Therefore, two of the three systems do require glucose as a source of fuel. Since we know that these systems are not exclusive, we can conclude that our body always needs glucose for energy. The way our body gets glucose is by nourishing it with carbohydrate. Complex carbohydrates are a major source of fiber in a diet. The recommended fiber intake for adults is 21 – 38 grams per day, depending on age and gender. The current, average fiber intake for Americans is approximately 15 grams per day.
It is estimated that at any given point in time approximately 80% of the population is suffering from some form of dehydration. Keeping your body well hydrated requires a constant effort and isn’t as easy as one would think or hope. Water is necessary for your body because it is a major component of plasma (60% of total blood volume), cerebrospinal fluid (the fluid that surrounds your brain and spinal chord) and synovial fluid (the fluid that lubricates your joints). Water is the major transportation mechanism in your body. It also plays an important role in temperature regulation and the distribution of solutes. If you are feeling thirsty you may be already displaying a sign of dehydration. But thirst isn’t always an adequate indicator of needing water replacement. Look for these signals: (1) failure to urinate for several hours, (2) production of a small volume when urinating and/or (3) dark urine color. Urine is 95% water by volume. Your body rids itself of one to two quarts of water each day due to urination alone; varying amounts are lost through breathing and insensible (continuous, unseen) perspiration. How much water do you need? This is based on your body size and activity level. For example, warm weather exercise can cause up to two quarts of water loss per hour from perspiration.
Knowing these facts about water you can now logically conclude that any change in your body weight is in part due to water loss. Wrestlers and boxers have known this for years; many of which have spent time in the sauna or exercising so that they make their fighting weight classification through weight loss due to water loss. A diet program that measures more than just your overall weight change will tell you if the change is due to something other than water loss. Now we’re talking about body composition, how much of your mass is comprised of fat. If you want a more accurate idea of your body composition you should consider a skinfold caliper measurement which a certified personal trainer or dietician can provide.
The best diets are those based on the modified food pyramid. The recommended dietary guidelines (as endorsed by the American Heart Association, American Cancer Association, American Diabetes Association, American Medical Association, American College of Sports Medicine, National Institute of Health, Centers for Disease Control and Prevention, and the American Academy of Pediatricians) for healthy individuals are as follows: 45 – 65 % carbohydrate, 10 – 35 % protein, and 20 – 35 % fat (less than 10 % from saturated/hydrogenated fats). The RDA for fiber is stated above. To approximate your daily protein requirements, you should know that most adults require only .8 grams per kilogram (.36 grams per pound) of body weight. However, adult athletes that are training vigorously may require 1.0 – 1.6 grams/kg/day (.45 – .75 grams/lb/day). For example: John is a competitive tri-athlete who weighs 200 lbs. He is actively training and can estimate his protein requirement at 120 grams per day (based on .6 g/lb body weight). However, when John is not training he should consider reducing his intake to 72 grams per day (based on .36 g/lb body weight).
Another way to look at your nutritional needs is to consider your caloric intake. Counting calories can be a laborious task. But perhaps this is what you may need to do in order to get a feel for portion size and balancing your nutritional needs. You can estimate your daily caloric needs (+/- 10%) to support your resting metabolic rate by using the Harris-Benedict Equation:
For males: 66 + (6.22 x body weight in pounds) + (12.7 x height in inches) – (6.8 x age)
For females: 665 + (4.36 x body weight in pounds) + (4.32 x height in inches) – (4.7 x age)
Next, you need to multiply your answer above by the activity factor below:
1.2 – 1.3 very light physical activity (sitting, driving, standing)
1.4 – 1.5 light physical activity (housecleaning, walking at 3.0 mph)
1.6 – 1.7 moderate physical activity (tennis, gardening, walking at 4.0 mph)
1.8 – 2.0 heavy physical activity (full court basketball, heavy digging, running long distance)
2.1 – 2.4 exceptionally heavy physical activity (competitive triathlete, Navy SEAL)
Use the above formula if you want to maintain your current weight. The key to weight management is one of supply vs. demand. Supply your body with the amount of calories that it demands to maintain your weight; consume more if you want to weigh more; or conversely, expend more and/or consume less if you want to reduce your weight. If your goal is weight loss, then try to create a 500 calorie/day deficit by expending 250 calories by exercising and consuming 250 calories less.
Be cautious of the high protein/low carbohydrate diets that are not balanced, are inadequate for major nutrients (i.e. carbohydrates) and micronutrients, low in fiber, and often high in cholesterol and saturated fats. Negative short-term effects of such diets may include: water loss (due to dehydration, not fat loss), suppressed appetites, muscle breakdown, nausea, constipation, headaches, lightheadedness, irritability, bad breath, kidney problems, elevated uric acid levels, and elevated BUN and creatinine levels. The long-term negative effects put you at risk for: colon cancer, heart disease, gout, and impaired kidney function. If weight loss is your goal, you should know that this kind of diet rarely provides permanent weight loss. And finally, there have been no controlled studies that prove its effectiveness and/or its safety. Have you heard of a major association putting its seal of approval on such diets? I have not. Have you read about a research study published in the New England Journal of Medicine or the Journal of the American Medical Association (JAMA) that supports the claims made by these diet promoters for long-term weight loss? I have not. There was only one short-term study funded by the National Institutes of Health that showed the weight loss after one year for high protein dieters was comparable to that of conventional dieters. The study showed positive results for triglycerides and HDL (good) cholesterol, which can be attributed to the fact that the dieters lost weight. In addition, I have heard from several clients and friends how their repeated attempts at these diets may have caused initial weight loss but later, after they stopped the restrictive diet, they gained weight beyond what they started at when they started the diet. Some of you may have heard this referred to as the “yo-yo” effect. My guess is that their dieting attempts didn’t teach them about balanced nutrition and that they reverted back to poor eating habits after they stopped following what some book told them to eat. It’s unfortunate for all of us that eating a healthy, balanced diet is not as convenient, or even as cheap, as eating a fast food/junk food laden diet.
Besides teaching group exercise and self defense classes, I work as a personal trainer assisting physical therapists and chiropractors in the rehabilitation of their patients. Recently, I was certified by the Cooper Institute as a Physical Fitness Specialist (Personal Trainer). My large course three ring binder, numerous training tapes, various books, client contact hours and their body composition measurements address the issues I stated above. But you don’t have to take my professional opinion. You don’t have to believe the testimonials of my clients. In fact, I want to help you make an informed, educated decision yourself. You can find nutritional information by searching out reputable sources such as: registered dieticians, the American Heart Association, the American Cancer Association, the American Diabetes Association, the American Medical Association and reputable scientific journals.
For further information you can reference the following books and/or websites:
- The Balancing Act by Georgia Kostas, RD, MPH
- Nutrition to Maximize Your Athletic Performance by Ellen Coleman, RD
- Jane Brody’s Nutrition Book
- Nancy Clark’s Sports Nutrition Guidebook
- Fit or Fat by Covert Bailey
- Syndrome X by Gerald Reaven, M.D.
- McArdle, W., Katch, F., and Katch, V., Essentials of Exercise Physiology, Lea and Febiger, 1994.
- American Dietetic Association www.eatright.org
- Centers for Disease Control and Prevention www.cdc.gov
- Cooper Clinic Nutrition Department/The Cooper Institute www.cooperinst.org
- Mayo Clinic www.mayohealth.org
- USDA Nutrition website: www.nutrition.gov
- For health fraud and quackery: www.quackwatch.com
DiAnn’s credentials include: Founder and Manager of W.O.W. – Women Only Workout, LLC which offers fitness classes and self defense for women courses (www.womenselfdefense.net), Cooper Institute Certified Physical Fitness Specialist, NDEITA Certified Group Fitness Instructor, Research Assistant for The Institute for Human Factors, American Women’s Self Defense Association (AWSDA) 2003 Seminar Instructor, and AWSDA Certified Rape Prevention Instructor. As a Physical Fitness Specialist, DiAnn works with Physical Therapists and Chiropractors in the rehabilitation of clinic patients.
You can contact DiAnn At:
W.O.W. – Women Only Workout, LLC
P.O. Box 13
Greendale WI 53129