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Dumping Excess Pounds By Dropping a Load— A Glycemic Load!
« poslato: Decembar 10, 2009, 02:07:28 posle podne »
Dumping Excess Pounds By Dropping a Load— A Glycemic Load!

A Glycemic Load

             Bodybuilders fret and worry about every last ounce of fat as they prepare for a contest. For those grueling eight to 12 weeks, calories are counted and carbohydrates are cut in the effort to reach an extremely low body fat. Once the stage lights dim, the temptation for an ice cream sundae may become overwhelming and pizza lures erstwhile athletes back into the comfortable zone of complacency with its siren song of sauce and toppings.

             With the exception of a rare few, most athletes, bodybuilders and celebrities relax their standards, gaining several pounds during their off-season. After the first few weeks to months, the added girth becomes uncomfortable and unpleasant by their standards, causing them to actively begin managing their weight again through a moderate diet plan.

             Everyone, even the larger-than-life celebrities created by sports and the media, worries about gaining excess weight. In addition to the pressure of being in the spotlight and the career need to look good, every person— public and private— has to consider the impact of extra fat on future health. Longevity and health are taken for granted by teenagers and young adults, but once issues like home ownership and teacher conferences become more important than music videos and all-night raves, it’s time to pay attention to health maintenance. Suddenly, the day will come when headlines about Heart Health and cancer prevention are as eye-catching as Ronnie Coleman’s biceps workout or a Halo 2 review.


Why Low-Fat Diets Don’t Succeed

The basics of losing weight are simple; take in fewer calories than you burn.1 For athletes, it’s more important to lose fat than weight, but the essentials are very similar. For years, dieticians had nice, long tables they could proudly display showing the calorie content of every food product. To add credence to their technique, they often teamed up with a health organization, like the American Heart Association, claiming their method would improve health and prolong the life span.2 The doctrine for years was to eat a low-fat diet, as the evil saturated fats that dripped from T-bone steaks and cheeseburgers would clog arteries and deposit squarely, (actually roundly, unless you are a yellow sponge), on your hips.

             Yet, as we have learned thanks to pioneers like Barry Sears and Robert Atkins, the traditional low-fat diet is no safer than other alternatives. In fact, low-carb/high-protein diets like the Zone and South Beach have been shown to be more effective in the short term and possibly even healthier alternatives than the carbohydrate- dominant, low-fat diets touted by dieticians and cardiologists.3-6

             In the search for an explanation for the relative failure of low-fat diets in facilitating weight loss and improving health, scientists have identified a likely culprit: refined carbohydrates.7 As the less well regarded high-protein diets have explained, to maximally promote fat loss, the release of insulin must be controlled.8 Insulin is a hormone produced by the pancreas, a gland located in the belly. When the body detects a rise in blood sugar, insulin is released and travels through the bloodstream. Insulin interacts with receptors on most cells and tissues in the body, the brain being the primary exception, starting a signal that drives sugar from the blood into active tissues, such as muscle.9,10

In addition to its action on blood sugar, insulin affects fat metabolism. When insulin is elevated, or if it remains elevated above normal fasting levels, fat cells are encouraged to store fat and are inhibited from releasing any stored fat.10,11 Other negative changes are also associated with persistently high insulin levels, including high triglycerides, low HDL (good cholesterol), high blood pressure, central (abdominal) obesity, increased risk of blood clots and chronic inflammation.10,12 This collection of problems is termed the metabolic syndrome and is being recognized as one of the greatest health threats facing the nation’s health care system.13


The Insulin Connection

Obviously, there are notable reasons to control insulin. Most people who are aware of insulin have a rough idea of how to manage it— by cutting down sugar in the diet. This basic level of understanding is an excellent start. Refined carbohydrates, whether they come from candy, bread, potatoes or pastries, flood the system with sugar and a vigorous insulin response is required to deal with the sugar tsunami.14,15 The insulin peak can remain elevated, even after the sugar levels have fallen back to normal. This accounts for the sudden lethargy that is experienced after a sugar rush, sometimes called an insulin dump.

 In some people, often sedentary individuals who tend to be overweight, the body becomes resistant to insulin’s signal and greater amounts of insulin are released for longer periods.13,15 The persistence of elevated insulin is a condition that precedes the metabolic syndrome. Some researchers believe insulin resistance is not just a component of the metabolic syndrome, but is actually the cause of the condition.10,12,16

             Dieticians recognize that the body does not respond to all carbohydrates in the same fashion. Simple sugars elicit a vigorous insulin response, but others induce a more mild insulin response. The insulin response appears to be related to the rate at which sugars from food are digested and absorbed into the bloodstream. Foods that quickly release sugar into the bloodstream cause a fast and large peak in insulin levels; such foods rate high on a scale called the glycemic index.14,15 Thus, sugary foods like kids’ cereals, white bread and many sports drinks are called “high glycemic index foods.” Carbohydrates that break down slowly, like whole grains and beans, release sugar into the system slowly and stimulate a mild insulin response; these are “low glycemic index foods.”

Beyond the concept of the glycemic index is a calculation called the glycemic load. The glycemic load of a diet is calculated by multiplying the glycemic index of a diet by the number of carbohydrates (in grams). The practice behind many of today’s Popular Diets is to lower weight and improve health by decreasing the amount of insulin released. Researchers recently published a study comparing a low glycemic load diet to a traditional low-fat diet relying upon breads and other high glycemic index foods on weight loss, metabolism and heart disease risk factors.17


New Research

In this study, two groups of overweight individuals were subjected to baseline measurements and then given prepared meals designed to induce weight loss by providing only 60 percent of calculated maintenance calories. The subjects were required to show up every day to eat the prepared lunch under the observation of the researchers; then they were provided with a prepared snack, dinner and breakfast to eat off-site with instructions not to eat any outside foods. After subjects reached a target weight loss of 10 percent of initial bodyweight, they were re-measured and comparisons were made between the two groups.

             The first measure of note was the effect of the different diets on blood sugar and insulin. As intended, after eating the prepared meals, blood sugar and insulin was twice as high in the group following the traditional low-fat diet. While the low glycemic load subjects reached target weight quicker, both groups took on average slightly over two months to lose 10 percent of their initial bodyweight. Neither group demonstrated an advantage in maintaining or developing lean mass during weight loss, but this is not surprising, as exercise was not part of the weight loss program.18

             On the surface, it would appear there’s no added benefit to controlling glycemic load, other than slightly quicker results. Bear in mind, these groups consisted of people who were not athletes, let alone bodybuilders. However, when examining the effect of the two diets through blood analysis and metabolic studies, the potential health benefits of lowering the glycemic load of the diet become evident. Perhaps, it might be more forceful to say the potential health risks of the traditional low-fat diet are exposed.

             Resting energy expenditure is a term used to describe the basal metabolic rate, or how many calories are burned at rest. Weight loss generally has a negative effect on resting energy expenditure, meaning it becomes more difficult to lose more weight because the body is trying to protect itself from starvation by burning fewer calories at rest. Though both groups demonstrated a drop in resting energy expenditure, the degree of reduction was twice as great for the traditional low-fat diet group (176 vs. 96 calories per day). This means the low-fat group burned fewer calories every day, increasing the likelihood of regaining weight and making it more difficult to maintain weight loss. Eighty calories per day does not sound like much, but it’s the caloric equivalent of walking one mile. All else being equal, the low glycemic load diet would allow for the loss of an additional eight pounds per year, every year.

Avoiding wild swings in insulin and blood sugar also seem to help control hunger, as subjects from the low glycemic load group reported being less hungry.


Important Discoveries

Blood analysis revealed some very important discoveries that could impact individual health and the health care system in general. As discussed earlier, insulin resistance is one of the early signs preceding the onset of the metabolic syndrome. Using a scale that measures insulin resistance, it was shown that while the low-fat group improved significantly, the degree of improvement was two times higher in the low glycemic load group.

             As would be expected using the metabolic syndrome model, as insulin resistance decreased, improvements were seen in nearly all the associated signs and symptoms. Serum triglycerides, fats that float in the bloodstream affecting the risk of vascular disease, were significantly lower in the low glycemic load group. While cholesterol values were not significantly different between the two groups, a dramatic effect was noted on the state of inflammation. Inflammation in the vascular system is believed to be the initiating event in blood clots that lead to strokes and heart attacks.19

Only recently has the importance of lowering vascular inflammation been recognized. This inflammation is measured by levels of a marker called C-reactive protein. In the low glycemic load group, C-reactive protein decreased by 50 percent, while it remained unchanged in the low-fat group. This revelation alone is sufficient reason to recommend lowering the glycemic load of the diet. Lastly, blood pressure was reduced to a greater extent in the low glycemic group, though the change was not significant. This may be a factor of the relatively few subjects in the study.

             It is amazing that the dogma of the established “experts” is constantly failing the scrutiny and challenge of close examination; yet, the dietary practices of bodybuilders are standing up to objective criticism by scientists. Despite the growing body of evidence supporting the experiences and recommendations that have been gained over the decades by dedicated and disciplined athletes, the media and many regulatory agencies continue to dispute the efficacy of the bodybuilding lifestyle.4,5 Whether this is due to professional pride, political influence or a media agenda, it is unfortunate. The public has been conditioned to scoff at the minority that considers physical development to be part of a well balanced life and suffers because it is being misled about issues that impact everyone at both an individual and societal level.20 As this study clearly shows, the old guard is not infallible and it is time to embrace new ideas.

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   2. Bunyard LB, Dennis KE, et al. Dietary intake and changes in lipoprotein lipids in obese, postmenopausal women placed on an American Heart Association Step 1 diet. J Am Diet Assoc, 2002 Jan;102(1):52-7.
   3. Yancy WS, Olsen MK, et al. A low-carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia: a randomized, controlled trial. Ann Intern Med, 2004 May 18;140(10):768-77.
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   8. McLaughlin T, Abbasi F, et al. Relationship between insulin resistance, weight loss, and coronary heart disease risk in healthy, obese women. Metabolism, 2001 Jul;50(7):795-800.
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  12. Deskalopolou SS, Mikhailidis DP, et al. Prevention and treatment of the metabolic syndrome. Angiology 2004 Nov-Dec;55(6):589-612.
  13. Unger RH. Minireview: weapons of lean body mass destruction: the role of ectopic lipids in the metabolic syndrome. Endocrinology, 2003 Dec;144(12):5159-65.
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  15. Pewlak DB, Ebbeling CB, et al. Should obese patients be counseled to follow a low-glycemic index diet? Yes. Obes Rev, 2002 Nov;3(4):235-43.
  16. Harris NS, Winter WE. The chemical pathology of insulin resistance and the metabolic syndrome. Med Lab Obs, 2004 Oct;36(10):20-25.
  17. Pereira MA, Swain J, et al. Effects of a low-glycemic load diet on resting energy expenditure and heart disease risk factors during weight loss. JAMA, 2004 Nov 24;292(20):2482-90.
  18. Tsai AC, Sandretto A, et al. Dieting is more effective in reducing weight but exercise is more effective in reducing fat during the early phase of a weight-reducing program in healthy humans. J Nutr Biochem, 2003 Sep;14(9):541-9.
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Written by Dan Gwartney, MD Online   
Monday, 07 December 2009