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Carbs: The facts behind the fad

If you need help getting a grip on the current carb fad, read what WebMD Weight Loss Clinic nutrition expert Kathleen Zelman, R.D., said when she joined us on WebMD Live.
/ Source: WebMD

The opinions expressed herein are the guest's alone and have not been reviewed by a WebMD physician. If you have questions about your health, you should consult your personal physician. This event is meant for informational purposes only.

Low-carbohydrate products are everywhere you look these days: Low-carb beer; low-carb chocolate; low-carb bread. And followers of Atkins and other similar diets have touted low-carb eating for years. If you need help getting a grip on the current carb fad, read what WebMD Weight Loss Clinic nutrition expert Kathleen Zelman, RD, said when she joined us on WebMD Live.

Moderator: Welcome back to WebMD Live Kathleen. Let's start with carbs 101. We hear so much about eating or not eating carbs, good carbs, and bad carbs. What are carbs?

Zelman: First of all, carbohydrates are the body's preferred form of fuel. All carbohydrates contain the same number of calories: 4 calories per gram. So whether you're eating an orange or drinking a soft drink, the calories of carbs are the same.

The terminology "good carbs" generally refers to carbs that are more than just empty calories. So good carbs would be in fruit, vegetables, whole grains, and even refined grains, because all of these foods have nutritional goodness. Even white rice, or the maligned white potato, contains vitamins and minerals. Products like brown rice are preferred to white rice, not because of the nutritional value, but because of the fiber. We all need plenty of fiber in our diets every day. One of the best ways to get fiber is from carbohydrates.

The other advantage of fiber is one type of fiber can help lower blood cholesterol. The other type of fiber slows down the absorption of food. It is this role of slowing down the absorption of food the reason why it has become known as the good carbohydrate.

Member question: What are the differences between net carbs and carbs?

Zelman: Net carbs is a creative terminology that has been crafted by the Atkins people. They use a formula to delete their version of bad carbs and come up with this creative terminology "net carbs." To the experts, the government, this terminology is meaningless. For example, in 1992 the federal labeling laws defined terminology, such as "low-calorie food" had to be 40 calories or less per serving. There is no such terminology for low carb or net carb that are regulated by the labeling laws. This, however, may change, but for the moment you're at the mercy of the food manufacturer.

Moderator: So claims in the ads for "low-carb" fast food are just smoke and mirrors?

Zelman: Potentially. Obviously, a burger without a bun has fewer carbs than with the bun, but some restaurants are cashing in, loading up on the unhealthy saturated fat and calling it Atkins-friendly food.

My advice to everyone who's trying to lose weight is to focus on the calories. Most experts in the scientific community agree that it is the calories that count at the end of the day. Of course, getting regular exercise while reducing your total calories is generally the best and preferred way to lose weight for good.

Moderator: So taking away the bun and adding cheese and bacon to a burger is not making the meal a healthier meal?

Zelman: Absolutely not. Adding bacon and extra fat does not make it healthier. Yes, it makes it lower in carbohydrates, but not healthier.

Moderator: Please explain how people lose weight on the no- or low-carb diet if they aren't healthy?

Zelman: Great question. There are a lot of misunderstandings about why these low-carbohydrate diets are so effective at losing weight if they're not the healthiest programs. Essentially, when you start a low-carbohydrate diet and the carbs are limited to roughly 20 grams per day, you go into a state of ketosis. The state of ketosis takes your appetite away and subsequently, even though you can eat all the protein that you like, while you're in ketosis you're not very hungry and the result is the low-carb diet becomes a low-calorie diet.

When we analyze the number of calories being consumed on these kinds of diets, we find that they are roughly equivalent to your basic low-calorie diet. Therein lies the answer to why you lose weight.

Member question: How many carbs should we be eating?

Zelman: The national guideline is a minimum of 130 grams of carbohydrates per day. We have found, at the WebMD Weight Loss Clinic, that we can use the range of 45 to 65 percent of total calories; that's the National Institutes of Medicine's guideline to find the perfect level of carbohydrates for most individuals. For example, athletes need the higher end of the range to give them energy to fuel their athletic sports, whereas some dieters do best on the lower end, or 45 percent, of their calories from carbohydrates.

The bottom line is that your body prefers carbohydrates, and while ketosis may work for the short term, there are no long-term studies validating the safety and efficacy of a low-carbohydrate diet.

Member question: How do you get any fiber if you are doing one of the no-carb diets?

Zelman: It's very difficult to get enough fiber on a low-carb diet, which is why constipation is a common side effect. If you are following a low-carb diet, make sure the carbs that you choose are high in fiber. Among the highest fiber foods are beans, which are also an excellent source of protein, whole-grain cereals, check the label for grams of fiber per serving, and of course whole fruits, vegetables, and in general, whole grains.

Member question: What types of veggies have high carbs in them?

Zelman: Most vegetables have about 7 to 10 grams of carb per half cup serving, except for starchy ones, such as peas and corn, which are similar to starches such as potatoes and rice.

Moderator: How do carbs affect the body?

Zelman: Let's use the example of a person that just wakes up in the morning with nothing in their belly. The first thing you consume is a glass of juice, which is all carbohydrate. The response in your body is for a sudden rise in blood sugar, because you're on an empty stomach and you've eaten nothing besides the simple carbohydrate. What follows is a rebound hypoglycemia, or low blood sugar. 

This peak and valley is what we try to avoid with carbohydrates, and you can avoid the surge and decline by drinking your juice with other foods, especially foods with fiber and whole grains. So if your breakfast was a glass of juice, an egg, and two pieces of whole-grain toast, the rise in blood sugar will be slower and steadier, as will the fall in blood sugar. The slow increase and slow decrease of a complex meal will take you from breakfast to lunch without hunger, whereas, the sharp fall and sharp rise is often associated with hunger, and leads to overeating.

So a diet that has foods with a low glycemic index (that's mostly the good carbs with lots of fiber) do not cause rapid increases or decreases in blood sugar and are more capable of controlling calories consumed.

Member question: Please explain the glycemic index. I always hear about it in talks about carbs. Where can I find it?

Zelman: There's a web site,, that has the glycemic index of foods and great explanations. In a nutshell, processed carbs tend to have higher glycemic loads than do unprocessed ones, and they result in a quick jolt of blood sugar that oftentimes leaves you very hungry when the blood sugar drops. This cycle of eating simple carbohydrates leads to frequent eating and overeating of total calories. By consuming carbohydrates that are lower in the glycemic load, for example, oatmeal, whole-grain bread, or fresh fruit, the load is less, you feel more satisfied, not as hungry, and tend to eat fewer calories.

Member question: Is a no carb diet safe for two weeks?

Zelman: Most healthy adults can tolerate a low-carbohydrate diet for short term. As I said earlier, we need long-term studies on the safety of these kinds of diets for a prolonged period of time. The worst feature about some of the low-carb diets is the restriction of healthy foods, such as carrots, pineapple, and bananas. These are nutritious foods that are good for you and should not be eliminated in a healthy diet.

Another concern about low-carb diets is when you limit carbs you naturally eat more protein and fat, and some of our favorite protein foods contain a great deal of fat. For example, bacon is a high saturated fat food and not healthy. So if you're on a low-carb diet, be very careful about choosing lean protein sources. It's better to eat salmon, all different kinds of fish, lean meat, poultry, skinless white meat of poultry, the lean cuts of pork, and pork tenderloin. These are the choices that will have the least amount of fat and be the best for you.

Moderator: A teaspoon of smoked cheddar, grated over eggs, can help you give up the bacon. The smoked flavor makes the difference.

Zelman: My only caution would be the American Heart Association recommends one egg per day for normal healthy adults. So be careful not to eat more than one daily.

Member question: Does eating low or no carbs help loose belly fat if that is where weight is gained?

Zelman: I think it's difficult to target areas of fat with select diets, but when you lose weight, generally you lose it all over your body. When you engage in regular physical activity you can help reduce in select areas. Check in with our WebMD exercise physiologist, Rich Weil. He'll be able to answer that question in more detail.

Member question: I've tried every diet I can think of and it seems the only way I can lose weight is to starve myself. Being a medical assistant I know that's not good for me, so what should I do?

Zelman: Join the WebMD Weight Loss Clinic and we'll show you the way to lose weight and keep it off once and for all.

Member question: So, basically what you're advising is a low-calorie diet and exercise?

Zelman: I know it's not sexy, but it's what works. You need to evaluate your lifestyle. What is it you're doing to gain weight? We can help you figure out which behaviors to modify, teach you the value of eating regularly, not skipping meals, and loading up on healthful foods, along with regular physical activity. Making small and gradual changes that result in one to 2 pounds weight lost per week is the answer to long-term success.

We have learned a great deal about successful weight loss from a group called The National Weight Control Registry. This is a group of successful losers, individuals who have lost substantial amounts of weight and kept it off for at least five years. Believe it or not, the easy part is losing the weight, because as you talk to your friends, most people on these low-carb diets are successful at losing weight. The real test is keeping the weight off. So the successful losers have shown us the way toward healthy weight loss, and these folks exercise regularly, follow a healthy, low-fat diet, journal their dietary intake, and they eat breakfast every day.

Give it a try. Eat breakfast, exercise. You know which foods are fattening. Cut back on them. Use portion control. Keep a little diary. The mere act of writing down what you eat has a powerful influence over your decisions.

Member question: What do you think of pills that promise to block the body from absorbing carbs or starch? Do they work?

Zelman: They're a band-aid approach to weight loss. My professional opinion is you should not use them.

Member question: As a diabetic should I still shoot for 45 percent of my diet from carbs?

Zelman: As a diabetic you really need to work with your physician and registered dietician to determine the best amount and distribution of carbohydrates in your diet.

Member question: I have always heard that fresh fruits had natural sugar in them and when consumed by our bodies turned into simple sugar.

Zelman: All carbohydrates, whether simple or complex, are reduced to sugar, or what we call glucose, in the body. Simple sugars get there more quickly than more complex sugars. The glycemic index is the tool that we use to determine the ranking of foods according to how quickly the sugar is released into the blood stream as glucose. Glucose is the sugar that the cells use for fuel. Some foods raise it faster and higher than others.

Member question: I am a runner, everyone tells me that carbs are bad for me but I've been taught otherwise. What should I be doing to drop weight and still have my energy to run?

Zelman: You're absolutely correct that as an athlete you need the energy and the carbs to fuel your running. Take a look at your total calories. You may need to reduce your calories or increase your activity to lose weight, but don't reduce the healthy carbs you need to fuel your running.

Member question: Does it make any difference what time of day I have my carbs? I love pasta but do not eat it for lunch because then I get hungry. If I have it for a late dinner then go to bed before I have a chance to eat again, will that be OK?

Zelman: The reason you probably get hungry soon after the pasta meal is that you're eating all carbohydrates. If you add some lean protein and/or healthy fats, throw some salmon into the pasta, handful of nuts, or chopped chicken, it will hold you longer and you won't be hungry two hours later.

Member question: How many calories are recommended per day for a healthy adult?

Zelman: The minimum of calories acceptable for women are 1200 to 1300, and men closer to 1500. Otherwise, it's hard to get all of the nutrients that you need from your diet and it is always best to get your nutrients from food instead of supplements.

In addition, these levels of calories should not make you hungry. When you reduce calories too low you live in a state of hunger, which is not healthy and leads to bingeing and attacks on the vending machine.

Moderator: So what's the bottom line on carbs?

Zelman: Last November a new study found virtually no difference in weight loss on four diets: Atkins, Zone, Ornish, and Weight Watchers, which used all different approaches toward weight loss. The bottom line is that everyone will respond differently to different diets. You need to find a diet that works for you in your lifestyle that's based on principles embraced by the national health organizations, such as the American Dietetic Assoc. or American Heart Assoc. Different strokes for different folks. Find the diet or program that you can live with for the rest of your life. If you haven't found it, keep looking.

Moderator: Do you have any final words for us, Kathleen?

Zelman: If you're overweight it's extremely important to not only your looks, but also to your health to lose weight. Losing as little as 5 to 7 percent you can reap huge health benefits. It's in your best interest to make those changes and start today. Good luck.

Thanks to Kathleen Zelman, MPH, RD/LD, director of nutrition for the WebMD Weight Loss Clinic, for being with us today. For more information please visit our nutrition center on WebMD. For a wider array of nutrition information, visit our message boards, such as Healthy Cooking with Elaine Magee, RD and Dieting with Martha McKittrick.