It seems in the diet industry, somebody always has to play the Bad Guy.
In the '60s and '70s, carbohydrates were the enemy. In the '80s and '90s it was fat — people got the idea that you could eat as much of anything you wanted as long as it was fat-free. Now, with obesity still on the rise, the pendulum has swung back to blame carbs again.
And when the pendulum swings, diet books and food products jump on for the ride. Those who follow such dieting trends used to down fat-free Snackwells and "lite" chips; now they are likely to have switched over to low-carb candy bars.
But many nutritionists warn that judging a food solely by its carbs is not any smarter than judging it only by fat content. While trends and fads come and go, the basics of healthful eating haven't changed — whole grains, vegetables, fruits, low-fat meats and dairy products, and exercise.
"Overall, people consume too many refined carbohydrate foods," said Beverly Webber, a University of Utah nutrition professor. "But oftentimes we read about new findings and overreact. Our bodies are usually much healthier if we eat fresh, wholesome, natural foods most of the time."
"Obesity is a disease of excess — excess calories and excess sedentary activities," dietitian Ken Ayoob, a pediatrics professor at the Albert Einstein College of Medicine in New York, is quoted as saying in the International Food Information Council's March April 2003 newsletter. "The cure is to balance calories in with calories out."
Some big diet buzzwords today are "glycemic index "and "insulin resistance." The glycemic index ranks carbohydrate foods by how quickly they enter the bloodstream and elevate blood sugar. Carbohydrates come in a variety of foods, from vegetables and fruits to pies and cakes. All carbs contain sugars, but they are in different forms. Some give up their sugars more readily — for instance, plain white bread produces blood sugar faster than pumpernickel. Once sugars enter the bloodstream, the pancreas pumps out insulin to get the sugars out of the blood and into the organs where it is needed, or into storage for future needs.
When sugars are absorbed slowly, the rise and descent in blood sugar is gradual. But when your pancreas detects a rapid rise in blood sugar, it pumps out a high level of insulin. The resulting plunge in the blood sugar level leaves a person feeling ravenous for more carbs, leading to a cycle of overeating. When this process is repeated over and over, the body's tissues become resistant to insulin, says Gary Heavin, founder and CEO of the Curves International weight-loss studios and author of the diet book "Curves." When the pancreas pumps out insulin but the body doesn't use it, this can cause the body to store fat, and possibly lead to Type II diabetes, he writes.
Keeping blood sugar level is a theme in many diet programs of the past few years — Atkins, Curves, The South Beach Diet, The Zone, Sugar Busters and Body for Life, to name a few. Although the methods and formulas vary, the general idea is to eat foods (or combinations of foods) that cause gradual increases and decreases in blood sugar, to satisfy your hunger longer. And to eat regularly to keep blood sugar levels from dropping and causing hunger.
On the glycemic index scale (or GI), "refined" carbohydrates, such as white flour, instant rice and snack foods like potato chips and French fries, are high on the list. Certain substances, including fat, protein and fiber, slow down digestion of carbs. That's why "whole" foods, such as a whole piece of fruit, brown rice or steel-cut oatmeal, keep you more satisfied longer than fruit juice, white rice or instant oatmeal. And why it's better to add a little turkey, lettuce and tomato before eating plain white bread.
At first glance it sounds simple to just avoid all foods with a high GI. "But you can't live by the glycemic index alone," cautions Utah State University food science professor Ann Sorenson, who is currently conducting research on the effect of food on blood-glucose levels in the hours immediately after a food is eaten.
For one thing, it's not always easy to figure out a food's GI. "You might think, it's sweet, therefore it's a sugar, but you can't predict only by sugar content," she said, pointing out that a baked white potato has a higher number than table sugar. The degree of processing, and the form of the food can make it digested easier into the blood stream. Mashed potatoes and french fries are higher than boiled potatoes.
Another problem — since the first index came out more than 20 years ago, numbers have been revised, and they vary among countries where the tests were done, as shown in the mammoth "International Table of Glycemic Index and Glycemic Load Values" published in the American Journal of Clinical Nutrition in 2002. Using white bread as 100, the index lists sweet corn as 84 in Canada, 69 in Australia, 86 in the United States, 53 in New Zealand and 89 in South Africa. Then the authors took the mean of those studies to come up with a score of 78. "Another reason GI values for apparently similar foods vary is that different testing methods are used in different parts of the world," the report stated.
Products can vary widely — a number may be given for a chocolate chip cookie, but different brands may have more sugar or fat or flour.
Another reason not to rely solely on the glycemic index for food choices is that many low- and no-carb foods are high in fat and calories, which can also lead to weight gain. Although short-term studies published in the New England Journal of Medicine suggests that low-carb regimes like the Atkins diet may help shed pounds faster and improve some risk factors for heart disease, conventional health experts have criticized its endorsement of saturated fats like bacon and butter. Some programs, such as The South Beach Diet, allow liberal use of "good" fats such as olive oil and nuts, but advocate using low-fat dairy, meat and poultry to cut down on saturated fat. The South Beach Diet, among others, also promotes eating non-starchy vegetables (lettuce, spinach, cucumbers, asparagus, broccoli, etc.) which have a low glycemic index.
"It's good to encourage people to increase their vegetable intake, and to eat more wholesome, natural foods," said Webber. "There is research that indicates the glycemic index can be of value, but we need to keep this information in balance and consume a variety of healthy foods."
It isn't healthy to drastically reduce our intakes of carbohydrates, she said. "We need to consume at least 100 to 150 grams of carbohydrates a day, preferable complex, to keep from feeling weak, tired, constipated and dehydrated."
Some foods with a comparatively high glycemic index contain important nutrients. For instance, the South Beach Diet recommends giving up all fruits and other starchy/sugary foods for the first two weeks.
"Fruit has a place in a balanced meal plan for normal, healthy adults, said Webber. "Fruit contains many important vitamins, phytochemicals and other valuable nutrients."
Potatoes are another high-G.I. food banished by some diets.
"I think potatoes are a good food and can be used in moderation like anything else," said Webber. "If you're having a piece of broiled or baked chicken, a baked potato, broccoli and a salad for dinner, know that you are fueling for health and energy and that is a good thing!"
She adds that anyone with diabetes or another health condition should see a qualified health professional to come up with a diet plan.
As usual, enterprising food manufacturers have seized the opportunity to come up with low-carb and sugar-free products. Atkins, EAS and Carb Solutions have shakes, protein powders and energy bars. Russell Stover, Hershey, and Nestle make sugar-free chocolate candies with sugar alcohols and other sugar replacers, which have little effect on blood sugar.
"We didn't want our regular consumers to deprive themselves of Russell Stover chocolates if they wanted to go on a low-carb diet," said company spokesman Terry Barber. The company makes both sugar-free and low-carb candies. "That, and the fact that the company president, Tom Ward, lost 25 pounds on a diet high in protein and low in carbohydrates."
Sugar replacers, like fiber, don't fully digest when they pass through the digestive tract. The chocolates mimic the taste and mouth-feel of real candy, but they are still high in fat and calories.
"If someone is trying to cut back on carbohydrates to control blood sugar levels but wants a sweet treat, this would be a good choice," said Pauline Williams, a dietitian with USU Extension who teaches diabetes education. "However, these chocolates should still be viewed as a treat, not a nutrient-dense food choice. These chocolates still have calories and very little contribution to vitamins, minerals and other health-promoting compounds. If the calories don't keep you from eating too many, the gastrointestinal side effects will. The undigested carbohydrate from the sugar alcohols can cause abdominal discomfort with bloating, gas and diarrhea."
Glycemic index table
This table lists the glycemic index of some foods:
Low:
Artichokes — below 20
Asparagus — below 20
Broccoli — below 20
Brussels sprouts — below 20
Cabbage — below 20
Cauliflower — below 20
Celery — below 20
Cucumbers — below 20
Eggplant — below 20
Beets — below 20
Collard greens — below 20
Spinach — below 20
Lettuce (all varieties) — below 20
Mushrooms — below 20
Okra — below 20
Peanuts — below 20
Peppers — below 20
Green beans — below 20
Zucchini — below 20
Boiled soybeans — 23
Low-fat yogurt, aftificially sweetened — 20
Whole milk — 39
Cherries — 32
Apple juice — 34
Grapefruit — 36
Moderate:
Whole-wheat kernels — 59
Spaghetti — 59
Meat-filled ravioli — 56
Fettuccine — 46
Whole milk — 39
Fat-free milk — 46
Fruit-flavored low-fat yogurt — 47
Navy beans, boiled — 54
Kidney beans, boiled — 42
Canned tomato soup — 54
Apricots — 43
Canned peaches — 43
Apple — 56
Pear — 47
Orange — 47
Plum — 55
High:
Muffin — 88
Angel food cake — 95
Croissant — 96
Hamburger bun — 87
Whole wheat bread — 99
White bread — 100
Bread stuffing — 106
Cheerios — 106
Rice Krispies — 117
White rice — 83
Taco shells — 97
Oatmeal cookies — 79
Vanilla wafers — 110
Jelly beans — 114
Pretzels — 116
Potato chips — 77
Boiled potato — 83
Mashed potato — 100
French fries — 107
Watermelon — 108
Pineapple — 94
Chocolate bar — 70
E-mail: vphillips@desnews.com