Like fashion trends, fad diets tend to come and go but one that has had a significant and long-lasting impact on the dietary habits of North Americans is the low-carb craze. The concept of cutting carbs for weight loss has actually been around for decades however it wasn’t until the past ten years that this approach skyrocketed to fame. The low-carb revolution lead to the creation of numerous diet books, low-carb products and even low-carb menus in many restaurants. While the popularity of ultra-low-carb diets and products have started to wane over the past year there continues to be a great deal of interest and research on carbs and their impact on health. So let’s take a closer look at this heavily scrutinized food group and sort out the carbohydrate conundrum.
The Good and the Bad
Carbohydrates are macronutrients – foods we need to eat in reasonably large quantities for health and wellness, compared to micronutrients (vitamins and minerals) which are needed in smaller quantities. The two other macronutrients required are protein and fat. Carbs provide our body with a readily available source of energy – glucose which is needed by every cell in our body. There are two main classes of carbohydrate: simple and complex carbs.
Simple carbs include sugars, such as glucose, fructose and lactose. Common sources of these carbs in our diet include table sugar (sucrose), candy, syrups and honey. These are referred to as “bad” carbs because they are linked to health problems such as weight gain, blood sugar imbalances, compromised immune function and dental caries.
Complex carbs are the “good” carbs and they include starches and indigestible dietary fiber. Common food sources of starches include, bread, pasta, rice, beans and some vegetables. Today many of our starches are refined and processed which greatly reduces their nutritional value. Common sources of dietary fiber are fruits, vegetables, beans, and the indigestible parts of whole-grains such as wheat bran and oat bran.
The typical Canadian diet consists of about 55 percent starchy complex carbs, about 5 percent are dietary fiber, and about 40 percent are sugary simple carbs. Simple carbs and refined starches provide virtually no nutritional value and since our increasing consumption of sugar and sugary foods is linked to health problems we should cut back on our consumption of these foods.
Carbs and Weight Gain
Carbs have certainly been pinpointed as a significant contributor to our obesity epidemic and there are several reasons for this. Carbohydrates are abundant in our food supply and found in a growing number of convenience and fast foods that we are feasting on. As well, many reports suggest that consumers are eating larger portions of carbohydrates, particularly the bad ones, so we are taking in more calories from carbohydrates. But the other important concept to understand with carbs and weight gain is how these foods are processed in our body.
Simple carbs (sugar and candy) and refined starches (white bread/pasta/rice) are broken down into glucose very quickly and are immediately absorbed into the bloodstream, causing a quick rise in blood sugar (glucose) levels. The body responds by triggering the pancreas to secrete insulin, whose role is to bring glucose into the cells to be used for energy. However in responding to the sudden rise in blood glucose, the pancreas typically produces too much insulin leading to hyperinsulinemia (high blood insulin levels). High insulin levels can trigger fat storage and hormonal changes that lead to weight gain. It also causes blood sugar levels to decline too low triggering hunger, fatigue and a foggy head feeling. And at this point our body says “give me more sugar” so we reach for that bagel or donut or candy bar to satisfy the hunger and cravings. As you see this can become a vicious cycle and it can also lead to health problems such as weight gain an increased risk of Type 2 diabetes.
Vegetables, fruits, beans and whole grains are handled differently. Because of their fiber content, these foods are broken down more slowly into glucose and they don’t raise blood sugar levels as fast as simple carbs. To help us understand the rate at which carbohydrates are broken down into sugar we can look at the glycemic index.
The glycemic index (GI) is a scale that measures how quickly carbohydrates are broken down into sugar. Those that are processed quickly have a high GI and as mentioned above simple carbs and refined starches fit into this category. Foods that are broken down more slowly into sugar have a low GI, such as most vegetables, fruits and unprocessed grains.
Numerous studies have linked diets high in the GI to obesity, insulin resistance and Type 2 diabetes and increased risk factors for heart disease. Researchers at the University of Sydney, Australia have done a great deal of research on the health risks of high glycemic diets. They have also tested hundreds of foods to obtain their GI score. To read more about the GI and see how your favourite carbs rate, visit www.glycemicindex.com
Choosing Your Carbs Wisely
Two important concepts to keep in mind when choosing your carbs are quality and quantity. Complex carbs are quality carbs because they are high in fiber are low in the GI, processed more slowly, and keep us feeling satisfied longer. The health benefits of high fibre diets are numerous and are known to reduce the risk of cancer, diabetes and heart disease. These foods are also full of health-promoting nutrients such as antioxidants, vitamins and minerals. So go for the whole grain breads and pastas and brown rice, vegetables, beans and fruit and pass on the white stuff.
The quantity of carbs consumed is also important, especially for weight management. Most health authorities recommend consuming 45-65% of calories from complex carbs. Keep in mind excess calories – whether they come from carbohydrates, fat or protein can be stored as fat. You may be surprised to learn that a serving of spaghetti is actually ½ cup, not the typical 2-3 cup portion that most restaurants and homes serve. The jumbo New York style bagels represent four servings!
Supplements Can Help
Cutting down on starchy carbs such as breads, pasta, potatoes, and baked goods can be difficult because these foods are convenient, abundant, and very satisfying to the palate. While portion control is important, there are also supplements available that can help lessen the impact of these foods. Several years ago, researchers discovered that an extract of the white kidney bean, known as Phase 2, can neutralize starch from the diet. The supplement works by temporarily inhibiting the action of an enzyme called alpha-amylase which is responsible for breaking starch down into sugar. When taken before meals, Phase 2 significantly reduces starch absorption, thus helping to promote weight loss and reduce the glycemic impact of the meal. Several clinical studies have been conducted on Phase 2 and found it to be safe and effective. There are no serious side effects or drug interactions. The recommended dosage is 1000 to 1500 mg before starchy meals.
So the bottom line on carbs is that they are an important part of a healthy diet. Choose low glycemic, complex carbs, control your portions, and use supplements to support a healthy lifestyle.