Weight Loss Research on Glycemic Index

Almost no difference in outcomes for 36 weeks of low-glycemic load diet in obese

No difference on health outcomes of high or low GI diet over 5 weeks

Relationship of GI to markers of health unclear

No differences in outcomes between low and high GI diets over 10 weeks (including satiety)

Review indicating some benefit in weight loss for low glycemic diets

2013 review indicating no anthropometric (fat loss included) differences between high and low glycemic index and load diets (This is the biggest nail in the coffin right here, as it’s a comprehensive review and is recent)

Weight Loss Research On Food Reward

Overall review of the food reward hypothesis

Additional research here

Increased Hunger and Slowed Metabolism

Extreme levels of overeating when high palatability food is presented

Energy restriction (for a whole year) shows only small (yet significant) declines in metabolic rate

Weight Loss Research and Metabolic Changes

MASSIVE weight loss rates (18kg in only 12 weeks) resulted in 67% of the weight loss predicted from NO metabolic adaptations. Thus, the idea that a slowed metabolism could account for a stoppage of weight loss is not in evidence. Furthermore, not all of the difference is explained by metabolic rate slowdown, further weakening its explanatory role in preventing weight loss

Metabolic changes only account for 120 calories–on average–of difference in metabolism during dieting, on average

Study showing 230 calories lower metabolism for a diet of 700 calories lower than maintenance levels (obviously not enough to stall weightloss)

The Yo-Yo Effect: Weight Regain

Weight regain occurs often, strategies to help it unclear

Review of behavioral interventions on weight regain show only small benefits

Weight regain for most diets highly common, solutions unclear

Weight Loss and Blood Sugar

Obese people have HIGHER blood glucose levels and HIGHER blood fat levels, not lower

Low-Carb Diets vs. Low-Fat Diets vs. Calorie Intake

Both low-fat and lowcarb nutrition plans work, no clear winner in this study either

Possible slight edge to low-carb, but results largely equivocal

No meaningful difference in weight loss of low-fat and low-carb

In controlled settings, most popular diets work about the same if they restrict energy to the same extent

The Science of Obesity

Fat went down only a small amount over time, carbs and calories up by a bunch

Percent of energy from fat decreased by only 3% from 1971-2006, but obesity went up 20%

Vegetarians and vegans take in much more carbohydrate, but are less overweigh than omnivores

Adam Bornstein

Adam Bornstein is a New York Times bestselling author and the author of You Can’t Screw This Up. He is the founder of Born Fitness, and the co-founder of Arnold’s Pump Club (with Arnold Schwarzenegger) and Pen Name Consulting. An award-winning writer and editor, Bornstein was previously the Chief Nutrition Officer for Ladder, the Fitness and Nutrition editor for Men’s Health, Editorial Director at LIVESTRONG.com, and a columnist for SHAPE, Men’s Fitness, and Muscle & Fitness. He’s also a nutrition and fitness advisor for LeBron James, Cindy Crawford, Lindsey Vonn, and Arnold Schwarzenegger. According to The Huffington Post, Bornstein is “one of the most inspiring sources in all of health and fitness.” His work has been featured in dozens of publications, including The New York Times, Fast Company, ESPN, and GQ, and he’s appeared on Good Morning America, The Today Show, and E! News.

The post Weight Loss Research appeared first on Born Fitness.

Editor’s note: This is part II of a combined post about common misconceptions on fat loss and weight gain. To read the first part, click here.

To help you understand why wheat isn’t the root of all evils, I’ve included an in-depth review of the claims made in Wheat Belly, as analyzed by Dr. Julie Miller Jones, Professor Emerita of Foods and Nutrition at St. Catherine University.

You can find the complete review and all study references here.

Wheat and Weight Loss

Davis’ Point: Elimination of wheat from the diet is the “holy grail” of weight loss. In his patient population, he recounts numerous occurrences of rapid, effortless weight loss of 10, 20, or even 50 or more pounds simply by elimination of wheat from the diet. He attributes the success of low-carbohydrate diets to the elimination of wheat.

What the Research Says:

Rapid weight loss often occurs with adhere to any weight loss diet in the short run. Studies and testimonials documenting dramatic weight loss abound, especially when the diets are low in carbohydrates (3-7).

Recommendations to eliminate wheat in conjunction with the other advice in this book reveal the Wheat Belly diet to be a low-carbohydrate diet. While it is truth that such diets have been shown to cause more rapid weight loss than other diets in the initial 6 months following such a regimen, they do not result in greater weight loss over time and result in more dropouts that other diet types that are more balanced and do not eliminate entire food groups.

Wheat and Obesity

Davis’ Point – Wheat consumption leads to central obesity. Central obesity stresses the heart, raises blood lipids, distorts insulin response, causes abnormal metabolic signals that affect every or- gan in the body, including the elevation of estrogen (which results in what he terms “men’s breasts”), and leads to inflammation.

What the Research Says:

Central obesity in the nutritional and medical literature is termed visceral adipose tissue (VAT). The facts Davis presents about central obesity are true and warrant concern.

What is not true is that wheat causes this condition and that elimination of wheat will cure this condition.

It is well documented that no one food or food group is responsible for VAT. Too many calories of any kind and too little exercise will result in VAT.

Recent data from the Framingham Heart Study cohort refute claims that wheat increases VAT. In fact, those who most closely adhered to dietary guidelines had the lowest VAT (17). Specifically, those who had the least visceral fat accumulation ate two servings per day of refined grains and three servings per day of whole grains (18).

Wheat and Expanding Waist Lines

Davis’ Point – The proliferation of wheat products parallels the increase in waist size.

What the Research Says:

Although the association may be true, this is an example of the misuse of correlations to imply causation.

First, the precise meaning of “proliferation of wheat products” is un clear. In many cases, less bread is eaten than was eaten in farm homes between 1900 and 1950.

However, more recent statistics from the U.S. Department of Agriculture Economic Research Service (USDA-ERS) show a 32% increase in wheat products since 1970 (19).

Davis does not report the more important information from the USDA-ERS paper (19), however, which notes, “A big jump in average calorie intake between 1985 and 2000 without a corresponding increase in the level of physical activity (calorie expenditure) is the prime factor behind America’s soaring rates of obesity and Type 2 diabetes…. Consumption in 2000 was 12 percent, or roughly 300 calories, above the 1985 level.”

Furthermore, many correlations can be made. Increasing waist size is associated with increased use of chewing gum, increased sales of running shoes, and the proliferation of high-fat ice creams, as well as any number of other products. Such associations are simply associations and do not prove causality.

The Twisted Glycemic Index

Davis’ Point – Whole-wheat bread has a glycemic index (GI) of 72, which is higher than table sugar (GI = 59).

What the Research Says:

Whole-wheat bread does have a GI higher than table sugar. GI is a measure that compares the blood glucose response elicited by 50 g of available carbohydrate from a food to the blood glucose response elicited by 50 g of glucose.

The GI of table sugar (sucrose) is directly related to its composition, which is half high-GI glucose and half low-GI fructose. Thus, the mixture of these two sugars results in a moderate GI, one that is lower than whole-wheat bread.

One aspect of GI that is frequently misunderstood is that the measure is often used to compare very different amounts of food. Fifty grams of sucrose or glucose (approximately 3 tablespoons) would yield fifty grams of available carbohydrate.

Fifty grams of available carbohydrate from whole wheat bread is much more than fifty grams of bread since bread is not all carbohydrate, and all the carbohydrate is not available.

Thus, it would take 144 g of whole-wheat bread (5.1 slices at 28 g per slice) or 111 g of white bread (3.9 slices) to yield 50 g of available carbohydrate.

Starches, Insulin, and Weight Loss

Davis’ Point – The relationships between blood glucose, insulin response, and GI, as described by Davis, include the following:

1) Whole-wheat bread consumption results in the same blood glucose response as white bread consumption: “Eating 2 slices of whole wheat bread increases blood sugar more than a candy bar.”

2) Pasta has a lower GI because of the compression of the wheat flour, but it does raise blood sugar at 4–6 hr.

3) A three-egg omelet causes no rise in blood sugar and no increase in insulin.

4) Whole-wheat bread consumption results in higher blood sugar levels than kidney beans or potato chips.

What the Research Says:

Davis’ statements regarding the relationships between blood glucose, insulin response, and GI are inaccurate and misleading.

1) Whole-wheat bread consumption does produce the same glucose response as white bread consumption. This statement by Davis is accurate; however, most users of the GI and glycemic load (GL) are unaware that the amount of bread is different.

It takes more whole-wheat bread than white bread to obtain the same glucose response.

Although it is also correct that wholewheat breads have a higher GI than a candy bar such as a Mars or Snickers bar, as previously mentioned the GI compares 50 g of available carbohydrate, which is about 4 slices of whole-wheat bread and about 2.5 oz of Mars bar, so the volume of food is different.

In addition, there are several factors involved in available carbohydrate levels, including the fat content of the food, which impedes amylase activity; other components such as nuts, a naturally low-GI food; and the rich phenolics and antioxidants in the chocolate, which lower the GI of the candy bar.

In short, because the calories and nutrients delivered by the two products are so vastly different, it is not possible to make a direct comparison that is meaningful.

It should also be pointed out that not all whole-wheat breads yield higher GIs; for example, some sourdough whole wheat breads (23) have a GI < 56, which is the value quoted for a Mars bar.

2) Pasta does have a lower GI than bread because the dense structure of the pasta impedes amylases from readily accessing the carbohydrate and, therefore, does not increase blood sugar rapidly (24).

Davis implies there is a problem because the pasta delivers glucose over a longer period of time. However, slow, steady delivery of glucose into the bloodstream is considered advantageous because it avoids large swings in blood sugar. Further, there is a ready supply of glucose for the brain and for use by cells throughout the body.

3) To state that an omelet causes no rise in blood sugar reveals a misunderstanding of the relationship between foods and their effects on blood sugar.

Although it is true that foods that do not contain carbohydrate do not raise blood glucose to a significant degree, the ingestion of protein can impact blood glucose by causing insulin release and through its digestion produce amino acids that are glucogenic.

Further, stating that an omelet does not raise insulin is incorrect. All food proteins stimulate insulin release (25), although not all stimulate its release to the same degree.

Foods such as milk, which has a very low GI, have a great capacity to stimulate insulin release through the release of incretin hormones and the presence of insulinotropic amino acids.

4) Whole-wheat bread does yield higher blood sugar than kidney beans or potato chips for several reasons. First, beans are a great source of dietary fiber, some of it soluble, which lowers blood glucose response.

Second, the carbohydrate in beans is less available. Potato chips have a lower glycemic response than whole-wheat bread because they contain more than 35% fat, and fat impedes amylases.

Further, starch in potato chips has been cooked and cooled, causing the starch molecule in the food to crystallize and produce a lower glycemic response.

Summary

Wheat Belly uses charges about the evils of wheat to tout the value of low-carbohydrate diets. While these diets have been shown to promote rapid weight loss in the medium term (6 months) and may be advantageous for individuals with metabolic syndrome and abnormal glucose tolerance, they have not been shown to be long-term solutions to obesity for most people.

The above statements were originally sourced from: “Wheat Belly—Analysis of Selected Statements and Basic Theses from the Book,” authored by Julie M. Jones, Cereal Foods World 57(4):177-189, 2012, AACC International, St. Paul, MN.

READ MORE: 

Beyond Bread: Why Some People Can Eat More Carbs Than Others

Fix Your Diet: Understanding Proteins, Carbs and Fats

Eating at Night Does Not Make You Fat

Adam Bornstein

Adam Bornstein is a New York Times bestselling author and the author of You Can’t Screw This Up. He is the founder of Born Fitness, and the co-founder of Arnold’s Pump Club (with Arnold Schwarzenegger) and Pen Name Consulting. An award-winning writer and editor, Bornstein was previously the Chief Nutrition Officer for Ladder, the Fitness and Nutrition editor for Men’s Health, Editorial Director at LIVESTRONG.com, and a columnist for SHAPE, Men’s Fitness, and Muscle & Fitness. He’s also a nutrition and fitness advisor for LeBron James, Cindy Crawford, Lindsey Vonn, and Arnold Schwarzenegger. According to The Huffington Post, Bornstein is “one of the most inspiring sources in all of health and fitness.” His work has been featured in dozens of publications, including The New York Times, Fast Company, ESPN, and GQ, and he’s appeared on Good Morning America, The Today Show, and E! News.

The post “Wheat Belly” – Understanding Wheat, Insulin & Fat Loss appeared first on Born Fitness.