Curb your refined carbs--not your "good" carbs

If you want to lose weight, are carbohydrates really the problem? Food experts say no--the problem with weight control is how many calories you consume.

Carbohydrates are necessary for life. But they come in a wide variety--don't throw out the good stuff just to lose weight.

By Deane Morrison

Published on July 22, 2005

The low-fat diet craze brought us a panoply of low-fat foods. Now, the various low-carb diets have spawned a similar response in the food industry. If you want to lose weight, are carbohydrates really the problem? Food experts say no--the problem with weight control is how many calories you consume. So cut the sugary drinks or refined-starchy snacks, but don't neglect the "good" carbs.

Sugars, starches, and fiber are carbohydrates. Common dietary sugars include simple sugars like glucose and fructose and double sugars like lactose, or milk sugar (glucose plus galactose), and sucrose, or table sugar (glucose plus fructose). When sugars are strung together by the thousands, they form large polymer molecules called starches. Starchy foods include not only well-known examples like potatoes, rice, and wheat, but also legumes such as beans and peas, which have a fair amount of carbs as well as protein. Starch is how many plants store energy, but people store energy mostly as fat. We do, however, store some glycogen, or animal starch, in our livers. Many marathon runners stock up on glycogen by eating spaghetti the night before a race, then deplete their stocks as they run.

"Don't micromanage your diet by obssessing over carbohydrates or fats," says Slavin. "Many low-carbohydrate foods are actually higher in calories than their original versions--not likely to help you lose weight."

Just as we need certain fats to live, we need a certain amount of carbohydrates in our diets to keep our brains, red blood cells, and other body parts working well, says food science and nutrition professor Joanne Slavin.

"If we don't get enough carbohydrates, our bodies will break down protein to get them," she says.

To make carbohydrates from protein, our livers strip nitrogen (carbohydrates lack nitrogen) from the carbon skeletons of amino acids (the building blocks of protein) and re-form those skeletons into carbohydrates. The discarded nitrogen is excreted as urea by the kidneys. Urea excretion requires lots of water, so people who shun carbohydrates may have to not only eat more protein but drink more water to make up the lack. But anyone who buys food knows that protein is the most expensive food. Therefore, eating more of it just for the sake of eating fewer carbohydrates is wasteful.

The U.S. Department of Agriculture's new dietary guidelines call for carbohydrates to constitute 45-65 percent of one's diet. Slavin recommends eating whole grain products, which contain fiber plus vitamins, minerals, antioxidants, and a host of other plant chemicals with various beneficial effects, including some that may protect against heart disease and certain cancers.

But the biggest problem with losing weight and keeping it off may be one of mindset. When dieting, many people seem to think there's an enemy that they must get rid of, says Slavin.

"I think it's the whole diet that counts--not just low fat or low carbs. It's not that simple. People want a list of what to eat, but we can't put it all in a can and make it perfect for anybody," she says.

In fact, dieting isn't really what weight loss is about. "Dieting" implies that once the weight is lost, the diet is over, and you're back to your old eating habits. No wonder so many people have yo-yo body weights. Rather, weight loss is about changing eating patterns for good. Reducing calories is the main thing. To keep weight off, exercise (muscles burn a lot of calories), eat a varied diet, and have a good breakfast. Breakfast tends to protect against weight gain, says Slavin. If you tend to crave sweets, include them in moderation so you run a lesser risk of bingeing on them. Best of all, cook your own food so you can control how much sugar and fat goes into it.

"Don't micromanage your diet by obsessing over carbohydrates or fats," says Slavin. "Many low-carbohydrate foods are actually higher in calories than their original versions--not likely to help you lose weight."

The best advice is probably Socrates' ancient prescription: Know thyself. Know how many calories you can eat without gaining weight, know the limits of your willpower, and be sure you get enough nutrients within those bounds. And bon appétit.