Unless you've got a Ph.D. in biochemistry, you're probably exhausted from the endless debate surrounding sugar.
And if your info has come largely from television, you're hopelessly confused. If you eat too little sugar, you don't have the energy to work out; too much sugar, and you get fat. Fortunately, getting the right kinds of sugar is really a simple matter of figuring out what kinds of sugar to eat—and when—to lose weight, build muscle, and protect your health.
Here's a look at which sugars are good for your body—and when you should eat them.
The science of sweet
All sugars are carbohydrates, known as "simple" carbs, since they're composed of just one sugar molecule. The label on a can of Pepsi reads 41g of carbs and 41g of sugar. This means that every single carbohydrate comes from sugar. The label on a package of plain oatmeal will read 18g of carbs and only 1g of sugar. Almost all of the carbs in oatmeal are made up of long chains of sugar molecules called "complex" carbs. Oatmeal—along with sweet potatoes, wheat breads, rice, and corn—is a complex carb.
But in this age of convenience foods, the terms "complex" and "simple" are a bit outdated. For the purpose of losing fat and building muscle, it's smarter to look at carbs as "unrefined" vs. "processed." The former refers to whole foods that contain sugar—fruits, vegetables, juices, grains, and legumes—while still holding onto their natural water, fiber, phytochemicals, vitamins, and minerals. "Processed" foods include white bread, soda, candy, crackers, cookies, and just about any commercial product labeled "fat-free." These have often been stripped of their wholesome attributes and are filled with nothing but "empty calories"—simple sugars, for instance. For example, 1g of a cracker will contain 4 calories, but 1g of an orange contains about 0.2 calories, because the bulk of its weight is water and fiber.
The glycemic index
The glycemic index rates how quickly certain foods turn into glucose (a form of sugar) in the bloodstream, and is a valuable tool when trying to control sugar intake and limit its effect on you. While high-GI foods can cause a rapid jump in blood sugar, followed by a massive crash, low-GI foods increase blood sugar slowly, providing constant and stable energy levels over a considerable period of time. Several factors contribute to a low rating, such as the presence of protein, fiber, and fat. Pure processed sugars garner the highest (i.e., worst for you) scores, with the most highly processed foods topping the list. For instance, out of a possible 100, instant rice earns a 90, while fibrous, vitamin-rich brown rice gets a 55.
So what's the difference? Recent studies by the Harvard School of Public Health show that diets loaded with high-GI foods lead to an increased risk of type-2 diabetes, coronary heart disease, and obesity. In fact, the World Health Organization is spearheading a movement to include GI ratings on food labels, and several products in Australia already bear the grade.
The dreaded insulin dump
Although sugar is lower in total calories per gram than fat, it contributes mightily to a fatty frame. "In our society, sugar is consumed in excessive amounts through unhealthy foods, and it increases total calories, leading to weight gain," says Eric Sternlicht, Ph.D., professor of kinesiology at Occidental College in Los Angeles, and president of Simply Fit Inc.
This effect is largely due to a hormone called insulin. The more highly processed sugar you eat, the greater the release of insulin from the pancreas. That's because the main role of insulin is to return blood-sugar levels to normal. However, when blood-sugar levels jump violently—which is what happens when you eat high-GI foods—your body pumps a massive amount of insulin into the bloodstream. This causes an overshoot, making blood-sugar levels bottom out, which triggers appetite, leading to a vicious cycle of overeating. In fact, sugar is often compared to a drug, rather than a nutrient, because of how it can leave you craving more instead of leaving you satisfied.
Overeating isn't the only danger. Some doctors, including Walter Willet, M.D., chairman of the department of nutrition at the Harvard School of Public Health, believe that years of eating processed food and experiencing the constant blasts of insulin can actually exhaust your pancreas' ability to produce insulin, putting you at risk for diabetes. Another condition, known as insulin resistance, can also develop, in which your body is so accustomed to insulin surges, the hormone loses its power to reduce levels of blood sugar. Recent research published in the British Medical Journal shows that men with elevated blood-sugar levels have a higher mortality rate from cardiovascular disease.
The upside of sugar
After all that, it's normal to think that sugar—or even carbs altogether—is essentially evil. But it does have its benefits, especially if you're active.
"Sugar has a bad connotation attached to it," says Sternlicht. "But in moderation, unrefined sugars are an important and vital part of your diet." Sugar that is needed for activity—such as weight training or a cardio workout—can be used as fuel, while any excess will be stored in the liver and muscles as glycogen for later use. Unfortunately, our storage space is limited, and anything left over turns to fat.
This balancing act is a result of science which shows that sugar boosts performance. "[Any kind of] carbs taken during exercise improve endurance performance, especially if an athlete is competing for a prolonged period of time during which stores would be depleted," says John Ivy, Ph.D., a professor in the department of kinesiology and health education at the University of Texas, Austin. "In fact, there's even some indication that carbs also improve short-term performance of intense exercise as brief as 20 minutes."
Each person reacts individually to sugar, but regardless of one's metabolism, paying strict heed to the following rules will keep your training efforts on track.
1. Limit refined sugars
Lack in nutrients and fiber, refined sugars are calorically dense, meaning they have lots of calories with little bulk. As a result, they don't put a dent in your appetite, so you can quickly eat too many. Sternlicht says no more than 15% to 20% of total carbohydrates should come from refined sugars. That's about 250 calories' worth in a 2,500-calories-a-day diet.
2. Choose unrefined sugars
Unrefined sugars are found in fruits, some vegetables, and other whole foods, and should make up the bulk of the carbs you eat every day. Fruits and vegetables still have fiber, water, and vitamins, so it's nearly impossible to eat too many of them. For example, the average man would have to eat about 50 oranges or 24lbs of cabbage per day just to maintain his weight.
3. Use sugar for peak performance
Despite its drawbacks, sugar is essential for tough workouts. "Not only do you need a source of sugar or other carbohydrate to restock glycogen stores necessary for enhanced athletic performance," says Sternlicht, "but carbohydrates are also needed to burn fat. With an inadequate amount of glucose in your system, you will be left feeling lethargic during workouts and unable to train effectively." High-glycemic foods such as Gatorade (78) or pretzels (83) are good choices for long hikes or runs.
4. Don't overdo it
Just because you work out doesn't mean you can eat a bowl of Pepsi-over-Cap'n Crunch for breakfast every morning. Your body still has a limited storage capacity for glucose, and excess sugars will be stored as body fat. That means you should eat unrefined sugar sources such as fruits, vegetables, and grains to trim down, while avoiding candy, soda, and other processed foods.
5. Time it right
A study in the American Journal of Physiology has shown that taking in sugar immediately before you exercise inhibits the fat-burning effects of cardio. If you run in the morning, do so before eating breakfast. If you work out in the afternoon, focus on foods that have a low glycemic index, and eat them at least two hours before hitting the pavement.
6. Eat your dinner before dessert
A food's glycemic index is affected by what you already have in your stomach or what you eat along with it. Avoid eating high-GI foods all by themselves. If you get a box of Godiva chocolates as a gift, be sure to dip into it lightly and only after a healthy meal.
7. Go easy on the sweet substitutes
The dangers of artificial sweeteners have been splattered all over the media. Scientists at the Clinical Pharmacology Group at the University of Southampton, United Kingdom, concluded in the journal Physiology and Behavior that intense sweeteners don't increase your tendency to snack, don't affect blood sugar or insulin levels, and may even help some people lose weight by lowering sugar intake. However, many high-profile and respected members of the medical community, including alternative-health guru Andrew Weil, M.D., are passionately opposed to aspartame and urge their patients to forgo it. In the end, as with anything, the best path is moderation.
The following is a list of some common natural sugars that can be a little friendlier to your physique than refined ones. Although unrefined, many of these sugars still pack a caloric wallop and can be detrimental if consumed in excessive amounts. Some are worse than others.
Date sugar: Made of ground-up dates. Rich with minerals and fiber.
Fruit juice: Absorbed into the bloodstream relatively slowly, creating only a moderate rise in insulin levels.
Honey: Will boost your energy, but contains more calories and rots teeth faster than sucrose (table sugar). Use in moderation.
Maple syrup: A sweetener that comes from maple-tree sap. Abundant in minerals, potassium, and calcium.
Sucanat: A product of squeezing juice from sugar cane. Similar to white sugar, but contains vitamins and minerals that table sugar doesn't.
Many of the following refined sugars can be found in some of your favorite foods. Keep your distance.
Blackstrap molasses: The liquid left behind after sucrose is removed from beet juice or sugar cane. Provides calcium and iron.
Corn syrup: Found in dozens of foods: salad dressings, lunch meats, ice cream, and canned fruits. Enhances viscosity, texture, and color.
Dextrose: Comes from the hydrolysis of cornstarch and serves as a yeast food in breads, buns, and rolls.
Brown sugar: A refined sweetener derived from sugar cane. Contains molasses syrup and is found in many baked goods.
Granulated sugar: Comes in many different forms. Can be found in anything from your sugar bowl at home to baked goods like doughnuts and cookies.
High-fructose corn syrup: Produced from adding enzymes to cornstarch. Found in soft drinks, ice cream, and frozen desserts. Invert sugar: An equal mixture of glucose and sucrose commonly found in carbonated beverages.
Aspartame: a bad rap?
Since being approved by the Food and Drug Administration in 1981, aspartame has been repeatedly panned in the media, for different reasons. There's no agreement on which component of aspartame is toxic: First, it was aspartic acid, then methanol, then phenylalanine, and now it's the diketopiperazine. Yet phenylalanine and aspartic acid are both amino acids found naturally in dietary proteins, and most dietary methanol comes from the digestion of fresh fruits and vegetables, not from aspartame. As for DKP, a whopping hit of 12.5g of aspartame given to six volunteers bore no adverse effects, says a study published in Food Chemistry and Toxicology.
As a result, aspartame is still considered safe by the FDA, the American Dietetic Association, and scientists who have tested it in humans at universities around the world. Even so, public fears persist, most likely because of reports that a large number of the population is unwittingly allergic to aspartame. However, according to the journal Modern Nutrition in Health and Disease, only a small segment of the population—one out of every 16,591—actually has this condition (called phenylketonuria), in which one cannot properly metabolize phenylalanine, one of the amino acids in aspartame.