All Carbs Aren’t Created Equal
▶ Understanding the differences between carbohydrates
▶ Discovering how the glycemic index is measured
▶ Making the best carbohydrate choices
▶ Presenting the dynamic duo weight-loss weapon: low-glycemic/high-fiber foods
Carbohydrates (which are found in foods and aren’t a food group of their own) are a big topic in the world of weight loss and health thanks to the low-carb craze and today’s numerous modified-carb diets. The problem is not all carbs are created equal, so you can’t treat them equally. You’ve probably heard or read about simple versus complex carbohydrates, fiber content, white versus whole grain, and so on. Throw in the glycemic index and figuring out what you’re supposed to focus on for your health gets really confusing!
But it doesn’t have to be that way. Yes, when considering carbs, you need to look at many factors, including the glycemic index, nutrients, and fiber. However, simple guidelines are available that can help you make the best choices for your health — and for successful weight loss.
This chapter presents some basics on what makes carbohydrates differ- ent and how the glycemic index comes into play so you can make the best choices for a healthy low-glycemic diet.
Distinguishing Friendly Carbs from Foes
To better distinguish carbohydrates that can help your diet from those that can harm it, you should really know a little basic info about carbs in general. Carbohydrates are your body’s major fuel source. They all break down into blood glucose, but they react differently in your body depending on their type. Carbs come in two varieties:
✓ Simple carbohydrates, which contain one or two sugar units
✓ Complex carbohydrates, which contain multiple sugar units
In the past, scientists thought that simple carbohydrates raised blood glucose levels quicker than complex carbohydrates because of the length of the sugar units. However, the latest discoveries with the glycemic index show that all carbohydrates, simple and complex, vary greatly in regard to their blood sugar response.
The glycemic index actually simplifies that technical mumbo jumbo a bit. Instead of focusing on complex versus simple carbs to find your best food choices for weight loss, you can focus on choosing low-glycemic foods that have a high nutrient content. Low-glycemic foods are therefore the new “friendly” carbs, and high-glycemic foods are the new “foes.”
Most people think of sugar, sweets, or white flour as simple carbohydrates that make for unhealthy choices. However, the issue isn’t quite that black and white. Consider the case of white flour. Often mistakenly lumped in the simple- sugars category, white flour is actually a complex carbohydrate, and complex carbs are typically labeled as “good carbs.” So not all complex carbs are necessarily the healthiest choices. White flour is an example of a high-glycemic “foe,” spiking the blood sugar much higher and faster than its whole-wheat counterpart (a low-glycemic “friendly” carb).
You can’t tell what food is friend or foe just by looking. Instead, the food must undergo scientific testing to determine how it responds in the body. Keep reading to find out how to know which foods are friends and which foods are foes.
Measuring a Food’s Glycemic Index
What makes a food low- or high-glycemic? First off, only foods that contain carbohydrates can be considered low-, medium-, or high-glycemic. Foods such as meats, poultry, fish, and fats (think oil and butter), don’t contain carbohydrates, which means you have to rely on your nutrition know-how to determine what kinds and how much of them to eat.
The glycemic level of a food measures how fast that food is likely to raise your blood sugar. A food that raises your blood sugar quickly is considered high- glycemic, and a food that raises it slowly is considered low-glycemic. Foods that fall somewhere in the middle have (you guessed it) a medium glycemic level.
Basing food choices solely on the glycemic index can be dangerous because that means you’re only looking at one aspect of food and ignoring other important ones (such as calories, amount and type of fat, and vitamin and mineral content). Many people think that whole grains, fruits, and vegetables naturally fall into the low-glycemic category. Although this is true much of the time, it isn’t always the case. Some of these foods actually have a high glycemic index, and many nonnutritious foods, like certain candies and chips, have a low glycemic index. Don’t simply take the road of “all low-glycemic foods are okay, so I can eat as much of them as I want.” That’s what happened during the lowfat craze of the ’80s and ’90s. People started eating fat-free everything, even if it meant higher sugar and calorie content. The same trend is emerging with low- glycemic foods; don’t give in to it!
The glycemic index is a great tool, but you also need to make sure you’re eating nutritious foods most of the time and not filling up on candy and chips just because they’re low-glycemic. Don’t toss everything you know about good nutrition out the window.
The next sections help you understand how scientists calculate the glycemic index and explain a few of the resulting caveats.
Comparing foods to pure sugar with human help
Because the glycemic index deals with your blood sugar’s reaction to various foods, determining a particular food’s glycemic index calls for the help of human test subjects. First, researchers feed 50 grams of available carbohydrates (that’s total carbohydrate minus fiber) to ten or more volunteers to test how the food raises blood sugar levels at different intervals over a two-hour period after it’s consumed. They then plot these changes in blood sugar on a graph and compare the volunteers’ responses to the test carbohydrate to their responses to the same amount of pure sugar or white bread. The average blood sugar response of all ten volunteers compared to their response to sugar or white bread deter- mines the glycemic index of that food item.
Researchers use pure sugar for comparison purposes because it’s the simple form of energy used by the human body. However, because most people don’t typically eat sugar all by itself, researchers have also been known to use white bread for comparison purposes.
Figure 2-1 demonstrates the sharp rise in blood sugar response when pure sugar is consumed. You can see the quick rise and the ensuing drop over time. Notice that the maximum blood sugar spike occurs around 45 minutes. After this peak, the blood sugar levels drop quickly.
Figure 2-2 shows what happens when a high-glycemic food is consumed. The rise is similar to what you see in Figure 2-1, but this high-glycemic food falls a little short of the curve set in the pure sugar test. The maximum blood sugar spike from a high-glycemic food occurs around 45 minutes after food consumption, with a fairly quick drop afterward.
Figure 2-3 shows the difference in the curve when a low-glycemic food is eaten. Notice that the maximum spike is much lower and also occurs much later, around an hour after consumption with a slow drop back to the base line. This type of blood sugar response results in lower levels of insulin being released and better control of food cravings, hunger, and mood.
Keeping a couple limitations in mind
As great as the glycemic index is, it does have a couple limitations due to how it’s measured. I bet you notice these differences as you begin coming across the various glycemic lists that are out there.
✓ The lists are limited. Glycemic index testing has only been around about 20 years, and it isn’t required by federal guidelines in the United States. The process is quite costly and time consuming because each variation must be tested. Also, only a small number of researchers actually conduct glycemic index testing, and they can’t possibly keep up with the thousands of new food products that manufacturers develop each year. Consequently, many foods haven’t been tested and are there- fore missing from glycemic index lists.
✓ The findings vary. The glycemic index must be measured by observing humans (specifically their blood sugar’s response to foods; see the preceding section), and no two humans are alike. That means the rate at which people digest carbohydrates, their insulin response, and even the time of day that they’re tested can cause variation. Therefore, each food must be tested by a group of people, and the results must be averaged together.
Also, there’s a lot of variability in the food world, which means inevitably all glycemic index charts aren’t going to be the same. For example, you may find one long-grain rice with a glycemic index of 62 and another with a level of 68. These differences may result from the grains being grown in different regions, the length of time they were cooked, how they were cooked, and so on.
The important factor to focus on is whether the food generally ends up high, medium, or low on the glycemic index. Don’t get too caught up in small number discrepancies among different glycemic index charts.
Defining Low-, Medium-, and High-Glycemic Foods
Determining whether a food is high- or low-glycemic is pretty straightforward. The glycemic index is broken into high-, medium-, and low-glycemic foods. High-glycemic-index foods have the quickest blood sugar response; low-glycemic-index foods have the slowest. Here are the measurements on a scale of 0 to 100:
✓ Low glycemic index: 55 or less
✓ Medium glycemic index: 56 to 69
✓ High glycemic index: 70 or greater
Keep in mind that high-glycemic foods aren’t necessarily unhealthy foods. Similarly, low-glycemic foods aren’t always healthy. The glycemic index simply lets you know how quickly your blood sugar will rise from eating that food.
The goal for weight loss on the glycemic index diet is to consume mostly nutritious low-glycemic foods and incorporate medium- and high-glycemic foods rarely. (Consuming a high-glycemic food once in a while isn’t going to make you gain weight overnight, so you do have some flexibility; Chapter 9 goes into more detail on the concept of moderation.)
Table 2-1 shows you the glycemic index numbers and measurements of some popular foods. As you can see, some foods fall right into line with what you may have thought about them. For example, brown rice is a low-glycemic food, and basmati white rice and spaghetti are medium-glycemic foods. But it’s not always that clear-cut. Notice how jasmine rice has a significantly higher glycemic index number than basmati rice even though both types of rice are white? This is where specific types of products vary. Even though foods of the same type may appear the same, each variety can produce a different blood sugar response for many reasons (the very nature and origin of the food may be different, people may prepare it differently, and so on).
According to Table 2-1, Peanut M&M’s and Snickers bars have the lowest glycemic content, whereas baked potatoes and watermelons have some of the highest. (No, candy isn’t suddenly healthier for you than a potato or fruit.) Labeling baked potatoes and watermelons as “bad for you” is a little unfair because they’re high in many different vitamins, minerals, and fiber. At the same time, you don’t want to assume that certain candy is great for you so you can eat as much as you want. That’s certainly rather tempting if you just go by the glycemic index numbers, but doing so will get you into trouble fast with your overall health and weight-loss goals!
Try prioritizing. First, focus on the basics of healthy eating. In other words, make sure you’re eating a balanced diet that features lots of fruits and vegetables, high-fiber starches, lean meats, and healthy fats. Next, for the foods that contain carbohydrates, choose those that are low-glycemic. (Because you can’t tell low-glycemic foods from high-glycemic ones just by looking at them, use Appendix A as a helpful guide.) Then to lose weight or maintain your weight, pay attention to portion size. After all, even too much of a good thing can be bad!
Seeing How Fiber Fits into the Mix
What’s a section about fiber doing in a chapter on carbohydrates? Trust me, there’s a definite method to the seeming madness. Turns out fiber is really just a term for complex carbohydrates that your body can’t break down. Not only that, it’s one of the most influential nutrition players for both weight loss and blood sugar control.
Plants use fiber for their shape and structure. In fact, fiber is what gives spin- ach its hearty stems. For humans, fiber can have many added health benefits, including heart health and intestinal health. The following sections reveal how fiber fits into your weight-loss plan.
Fiber and blood sugar control
Following a low-glycemic diet is about managing your blood sugar so you avoid large insulin spikes throughout the day. Fiber is a natural part of this process. Along with its other weight-loss benefits, fiber helps control the rise of blood sugar in your body after a meal. This effect is found specifically in soluble fiber, which dissolves and becomes gummy. Soluble fiber is also great at reducing cholesterol levels. Insoluble fiber, which people often consider “roughage,” is also beneficial. It works as an appetite suppressant, slows the rate that blood accepts the blood glucose that’s formed from digested sugars and starches, prevents constipation, and decreases your risk for bowel diseases.
In some cases, diabetics have been able to come off of medication because a high-fiber diet was enough to control their blood sugar. Additionally, The New England Journal of Medicine noted that diabetics who ate about 50 grams of fiber had much improved blood sugar control. Pretty impressive for a food you don’t even digest, huh?
Clearly fiber is an important part of your overall weight-loss plan. You should try to consume 20 to 35 grams of fiber per day, including at least one to two servings of soluble fiber. This means eating about five servings of fruits and vegetables, three servings of whole grains, and one serving of legumes each day. Following are some specific foods that are high in both soluble and insoluble fiber (be sure to add ’em to your shopping list):
✓ Soluble-fiber foods: Beans, peas, oats, barley, flaxseeds, and many fruits and vegetables (such as apples, oranges, and carrots).
✓ Insoluble-fiber foods: Whole-wheat bread or pasta, corn bran, and many vegetables (such as green beans, cauliflower, and potatoes). The tough, chewy texture of these foods comes from the fiber itself.
The fiber content of vegetables and fruits varies considerably. For example, applesauce doesn’t give you as much fiber as an apple with the skin on. Similarly, a large bowl of salad using only Romaine lettuce has around 1 gram of fiber compared to almost 4 grams of fiber for 1 cup of boiled collard greens.
This simple fact is why aiming for a variety of fruits, vegetables, beans, and grains is the way to go.
Low-glycemic/high-fiber, a winning combination
Fiber is an excellent weight-loss tool — in fact, it’s one of the most important weapons in your weight-loss arsenal. The beauty of fiber is that it has no calories. Nada. Zero. Zilch. Why? Because your body can’t digest or absorb it. This lovely fact of nature means fiber adds more volume and bulk to your meals for fewer total calories. Fiber’s bulk also helps you stay full for a longer period of time. When you chow down on foods that are low-glycemic and high in fiber, you’re getting the best of both worlds.
The next sections explain the weight-loss benefits of this winning combination, highlight some low-glycemic/high-fiber foods worth trying, and illustrate how to incorporate these foods into your meals.
Checking out what the low-glycemic/high-fiber combo can do for you Choosing foods that are low-glycemic and high in fiber is your secret weapon for weight loss. This power-duo combination adds up to
✓ Lower blood sugar and insulin spikes
✓ Controlled food cravings
✓ A longer-lasting “full” feeling
✓ Fewer calories and more volume consumed
Low-glycemic doesn’t always mean high fiber
It should go without saying that all low-glycemic foods must be high in fiber . . . right? Well, not exactly. You can easily assume that all high- fiber foods are low-glycemic. However, some foods (such as Peanut M&M’s) are low in fiber but have a lower glycemic index than say, potatoes, which are high in fiber. Even though fiber is a strong component in controlling blood sugar spikes after a meal, no one quite knows why.
The glycemic index is all about accounting for the food as a whole and its effect on blood sugar, not specifically measuring fiber. Expect to find a mix of fiber content when looking at low-glycemic foods. For example, potatoes are high in fiber, 4.6 grams for a baked potato with skin, yet they wind up being a high-glycemic food. Fortunately, most vegetables, fruits, and beans end up as low-glycemic, making life much easier!
So how to make sure you’re getting enough fiber out of the large variety of low-glycemic fruits, vegetables, beans, and whole grains you’re eating? Good news! You don’t need to mess with counting fiber grams. Instead, just aim for the following:
✓ Three or more servings of vegetables each day
✓ Two or more servings of fruits each day
✓ Three or more servings of whole grains each day (out of your total grain intake)
✓ One or more servings of legumes (beans, peas, and lentils) each day Reviewing common low-glycemic/high-fiber foods
Meeting your fiber quota while incorporating low-glycemic food choices into your weekly meal plans is easier than you may expect. Table 2-2 shows you several popular low-glycemic/high-fiber foods.
Incorporating low-glycemic/high-fiber foods into each meal Incorporating low-glycemic/high-fiber foods into your diet is as simple as focusing on eating a wide variety of plant-based foods. If you can manage that, you’ll be on your way to a healthy fiber intake for the day. Following is a sample menu that uses some of the food choices presented in Table 2-2.
Pointers for fiber newbies
If you aren’t used to eating a high-fiber diet, or if you plan on increasing your fiber intake, you should keep a few key things in mind:
✓ Drink eight to ten glasses of water a day .
Fiber holds onto water like a sponge as it “sweeps” your intestinal track, so keeping up with your daily water intake helps fiber work more efficiently. An added bonus: Drinking enough water helps you avoid feeling gassy or bloated.
✓ Ease into fiber instead of jumping in all at once . If you’re only eating an average of about 10 grams of fiber a day, you’ll feel gassy and bloated if you suddenly increase your fiber intake to 35 grams. Gradually start eating more fiber over the course of a week and see how you feel.
✓ Note that a significant amount of high-fiber foods can fill children up quickly . Although fiber is an important part of a child’s diet, you should make sure she doesn’t end up eating too few calories because she feels full from too much fiber. A high-fiber diet is good for adults who want to lose weight, but it may affect growing children differently.
✓ Check with your doctor if you’ve had any intestinal issues or gastrointestinal surgery . In either case, increasing your fiber intake may have undesirable con- sequences for you, so talk to your doctor before pumping up your fiber servings.
To create similar meal plans on your own, cross-reference your fruit and veggie choices with a glycemic index chart to make sure the foods you’re picking are low-glycemic as well as high in fiber. Then think of a way to add a serving of legumes into your day (perhaps by tossing a cup of beans into your lunchtime salad). Finally, as you’re choosing your whole grains, remember this rule of thumb: the higher the fiber (generally) the better.
Not really sure how to incorporate more low-glycemic foods into your diet? Check out Chapter 7 for some ideas. Also take a look at Chapter 15, which provides some simple recipe makeovers to illustrate how high-glycemic meals can become lower-glycemic ones with a few basic swaps.
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