Let's start with basic nutrition. There are many kinds of nutrients, of which carbohydrates, or "carbs" for short, is just one. Other nutrients include proteins, fats, vitamins, minerals, and water.
Whether trying to lose or maintain weight, improve blood sugar control, or prevent heart disease, calories count first, no matter what form they are in: carbs, fats, or proteins. And depending on your health goals, the idea is to find the balance of calories and nutrients that works best for you. No one diet works for all people.
Carbohydrates are the body's primary and preferred source of energy. When you eat carbs, the body converts them into glucose, or blood sugar, which the body's cells use for fuel. Think of your body as a car, with fuel, or blood sugar, being added at the gas pump. When the fuel enters your body, a hormone called insulin unlocks the body's cells and allows the fuel to be absorbed.
Carbohydrates contain four calories per gram. They can come in a simple form called sugar, commonly found in foods such as candy, soda pop, cakes, pies, cookies, and ice cream. Carbohydrates can also come in more complex forms, sometimes called starches, like bread, grains, vegetables, and fruits. And finally, carbohydrates come in an indigestible form called fiber, or roughage. Fiber is found in foods such as whole grains, fruits, and vegetables and is important because it helps to slow and regulate sugar entering the bloodstream. Fiber also provides other health benefits: it helps reduce cholesterol, aids digestion, and prevents constipation and possibly colon cancer.
People with diabetes must carefully control the carbs they eat to avoid blood sugar highs and lows. Using the car analogy again, when too much fuel enters the body too quickly, blood sugars can "spill" out into the bloodstream, raising levels. Too much blood sugar can also cause the cells to become resistant to insulin. If you are overweight by as little as 20 pounds or have too much blood sugar or insulin resistance, it can lead to a host of health problems, up to and including prediabetes, diabetes with all of its complications, and raised triglycerides (blood lipids or fats) that are implicated in heart disease.
After carbohydrates, fats are the body's secondary choice for energy, and they are also the preferred form of calories for storing body fat. Fat has nine calories per gram, or more than twice as many calories per gram as carbs. Fat calories, however, do not raise blood sugar. Fat in a meal actually helps control weight because it increases digestion time and makes you feel full. When you eat fats, some will be used for energy, but excess amounts will be stored as body fat.
The fat calories you eat, if chosen wisely, can help prevent heart disease. For example, saturated fats and cholesterol in the diet are associated with heart disease, while foods high in omega 3 fatty acids, such as salmon and walnuts, are associated with improved heart health. Some fats, such as hydrogenated fats found in margarine, shortenings, and many packaged foods, contain trans-fatty acids, a form of fat associated with many health problems, including heart disease.
Your body's least favorite source of energy is protein because it takes longer to be converted into glucose. Proteins, with four calories per gram, are essential for growth and maintenance of muscle mass, but watch out for the fat that lurks within proteins, not only for weight control but also for your heart's health. When you eat protein it enters the small intestine where it is broken down into molecules of amino acids. These are absorbed into the bloodsteam and sent to the liver where some are converted into glucose, or blood sugar. However, the process takes some time and is not a major contributor to high blood sugar. Some of the amino acids are used to build new protein.
Three keys to long-term weight control and good health can be clearly stated: 1. balance the amounts of carbohydrate, protein, and fat that your body needs to function properly; 2. eat healthful foods, such as carbs high in fiber and healthy fats; 3. and burn excess calories by activity and exercise.
Keeping Carbs Low
How low is a low-carb diet? There is no standard definition. Registered dietitians recommend a minimum of 130 grams of total carbohydrate daily, that is, the minimum required for normal functioning of the brain and nervous system. Because the long-term effects of following a very low-carbohydrate diet are still unknown, we would not advocate eating fewer than 130 grams of carbohydrate daily, which can be considered "low" compared to the Dietary Reference Intake-recommended amount of 45–65% of total calories from carbohydrates (45% of a 2000-calorie diet is 225 grams of carbohydrate; 65% is 325 grams of carbohydrate).
Net Carbs and The Glycemic Index
New research in carbohydrate metabolism indicates that not all carbs are created equal. We also took "Net Carbs" and the "Glycemic Index" into account when we developed the recipes for 1,001 Best Low-Carb Recipes.
The net carb is based on the belief that fiber sources of carbohydrate are not absorbed by the body and therefore are calorie-free, do not affect blood sugars, and do not contribute to weight gain. Since this is the case, fiber carbs can be subtracted from the total carbohydrate count of a recipe or food. The total carbohydrates minus the fiber carbohydrates leaves the "net" carbs available to the body. This difference between the total carbs and fiber is also known as "impact carbs," as these are the carbs that have an "impact" on the body. In this book we chose to use the term "net carbs," and this figure is provided with each recipe.
In addition, some carbohydrates increase blood sugar faster than other carbohydrates. The speed at which carbs are converted to blood sugar has been measured for some foods and is called the glycemic index. The higher the G.I. number, the faster the carbs change to blood sugar. With high G.I. foods, the rapid rise in blood sugar causes insulin, a hormone produced in the pancreas, to peak, resulting in a rapid drop in blood sugar, which then leads to hunger, snacking, and overeating. The lower the G.I. number, the slower the carbs change into blood sugar and the less insulin is released, which results in less overeating.
White bread and white sugar get the highest G.I. value of 100. When you choose carbohydrate foods to complement recipes in this book, pick those with both low net carbs and low glycemic indexes. For example, if rice is served with a stir-fry recipe, brown rice would be the better choice since it has a G.I. of 50 compared to 56 for white rice. Or, if breakfast includes fruit, ½ of a grapefruit has a lower G.I. than a banana.
The chart below lists a variety of commonly consumed foods with known glycemic indexes.
FOOD Glycemic index (glucose = 100)
HIGH-CARBOHYDRATE FOODS
White wheat bread* 75 ± 2
Whole wheat/whole meal bread 74 ± 2
Specialty grain bread 53 ± 2
Unleavened wheat bread 70 ± 5
Wheat roti 62 ± 3
Chapatti 52 ± 4
Corn tortilla 46 ± 4
White rice, boiled* 73 ± 4
Brown rice, boiled 68 ± 4
Barley 28 ± 2
Sweet corn 52 ± 5
Spaghetti, white 49 ± 2
Spaghetti, whole meal 48 ± 5
Rice noodles† 53 ± 7
Udon noodles 55 ± 7
Couscous† 65 ± 4
BREAKFAST CEREALS
Cornflakes 81 ± 6
Wheat flake biscuits 69 ± 2
Porridge, rolled oats 55 ± 2
Instant oat porridge 79 ± 3
Rice porridge/congee 78 ± 9
Millet porridge 67 ± 5
Muesli 57 ± 2
FRUIT AND FRUIT PRODUCTS
Apple, raw† 36 ± 2
Orange, raw† 43 ± 3
Banana, raw† 51 ± 3
Pineapple, raw 59 ± 8
Mango, raw† 51 ± 5
Watermelon, raw 76 ± 4
Dates, raw 42 ± 4
Peaches, canned† 43 ± 5
Strawberry jam/jelly 49 ± 3
Apple juice 41 ± 2
Orange juice 50 ± 2
VEGETABLES
Potato, boiled 78 ± 4
Potato, instant mash 87 ± 3
Potato, french fries 63 ± 5
Carrots, boiled 39 ± 4
Sweet potato, boiled 63 ± 6
Pumpkin, boiled 64 ± 7
Plantain/green banana 55 ± 6
Taro, boiled 53 ± 2
Vegetable soup 48 ± 5
DAIRY PRODUCTS AND ALTERNATIVES
Milk, full fat 39 ± 3
Milk, skim 37 ± 4
Ice cream 51 ± 3
Yogurt, fruit 41 ± 2
Soy milk 34 ± 4
Rice milk 86 ± 7
LEGUMES
Chickpeas 28 ± 9
Kidney beans 24 ± 4
Lentils 32 ± 5
Soya beans 16 ± 1
SNACK PRODUCTS
Chocolate 40 ± 3
Popcorn 65 ± 5
Potato crisps 56 ± 3
Soft drink/soda 59 ± 3
Rice crackers/crisps 87 ± 2
SUGARS
Fructose 15 ± 4
Sucrose 65 ± 4
Glucose 103 ± 3
Honey 61 ± 3
Data are means ± SEM.
Choose the Right Ingredients
In developing recipes for this book, we were careful to select carbs with low glycemic indexes and have, where possible, used whole-grain pastas rather than white semolina flour pastas, whole wheat flour rather than all-purpose white flour, brown rice instead of white rice, and brown sugar or sugar substitute instead of white sugar.
Fat in a meal helps control weight by increasing the time it takes to digest that meal, thus delaying the onset of hunger. Fat works with the low-glycemic foods to help improve your sense of fullness and satisfaction, which is why the recipes in this book mostly use full-fat products. As a bonus, full-fat foods frequently have fewer carbohydrates than the lower-fat products.
Trans-fatty acids, which are associated with LDL ("bad") cholesterol and heart disease. On the other hand, monounsaturated fats, the kind associated with HDL ("good") cholesterol, are considered healthy for the heart. These include olive oil, flax seeds and their oil, and walnuts and their oil; fatty fish like salmon or mackerel also contain monounsaturated fat. Olive oil and canola oil are used for most of the recipes in this book because of their monounsaturated fat content.