When Atkins first published his ''Diet Revolution'' in 1972, he promised that we would lose weight eating steak, eggs and butter, because it was the carbohydrates – the pasta, rice, bagels and sugar – that caused obesity. Fat, he said, was harmless. Atkins allowed his readers to eat luxurious foods without limit – steak with cream sauce, bacon cheeseburgers – but allowed no starches or refined carbohydrates – no sugars, rice, potatoes or anything made from flour, not even fruit juices or brown bread. Long-term however, consuming an unlimited intake of saturated fats and cholesterol-rich food causes heart disease and excessive calcium excretion in urine (increasing the risk for kidney stones and osteoporosis). Not surprisingly, Atkins had to defend his diet in Congress.
Anyone who has stopped eating carbohydrates to lose weight will tell you that doing so, works. But they will also tell you that it is not a happy existence – a life without carbohydrates is no life at all! So we know that in excess quantities (especially the “wrong” kind), carbohydrates can lead to weight gain. But how do you know which is the “wrong kind”? In other words, how can you lose weight without having to give up carbohydrates entirely?
The best way to differentiate between the “right” and the “wrong” carbohydrates is to understand the Glycemic Index. The basic idea is that compared to fats and protein, carbohydrates have the greatest impact on blood sugar because they are converted into glucose by the body. And because the body cannot store more than one day’s worth of glucose in the liver and muscle tissue, excess quantities will be stored as body fat. In other words, the amount of carbohydrates eaten – rather than fats or proteins – will determine how high blood sugar levels will rise – and how much body fat you will accumulate.
The Glycemic Index (GI) is a ranking of food on a scale from 0 to 100 according to the extent to which it raises blood sugar levels after eating.
To determine a food's GI rating, measured portions of the food containing 10 - 50 grams of carbohydrate are fed to 10 healthy people after an overnight fast. Finger-prick blood samples are taken at 15-30 minute intervals over the next two hours. These blood samples are used to construct a blood sugar response curve for the two hour period.
Foods with a high GI (scoring >55 on the GI tables) are those which are rapidly digested and absorbed and result in marked fluctuations in blood sugar levels.
Foods with a low-GI (scoring <55>
*for a complete table, visit: http://www.glycemicindex.com/
With the GI diet, you can lose weight while still eating carbohydrates – you just have to know what kind of carbohydrate is the “right” kind. As a general rule, complex carbohydrates are low-GI foods, and simple carbohydrates are high GI foods. This is because complex carbohydrates are broken down more slowly than simple carbohydrates, keeping you from feeling hungry and providing a more consistent stream of energy. They are also more likely to provide more vitamins and minerals, as well as fiber (helping with digestion). Simple carbohydrates add calories, increase blood glucose levels quickly, and provide little or no other nutrients.
| Low-GI foods (complex carbohydrates) | High-GI foods (simple carbohydrates) |
| Non-starchy vegetables Whole grains: e.g. oats, brown rice, quinoa, wheat, couscous Beans and legumes: e.g. garbanzo, lentils, kidney beans Nuts and seeds: e.g. chia, linaza, walnuts, peanuts Milk Less-sweet fruit: e.g. apples, grapefruit, pears, bananas | Table sugar, sugar cane, honey, and corn syrup and all foods made with these (e.g. cookies, cakes, soda, candy, ice cream) Refined white rice Refined white flour and all foods made with these (e.g. white bread, pasta) Starchy vegetables: e.g. yucca, potatoes, corn Sweet fruit: e.g. pineapple, grapes, kiwi, melon, peaches |
Eating according to the Glycemic Index can also help prevent diabetes. This is because high-GI foods cause blood sugar levels to spike, and the body to create excess amounts of insulin (the substance which moves glucose out of the bloodstream and into cells, where it is used for energy). If you’re eating high-GI foods meal after meal, snack after snack, day after day, there is a great deal of stress on the system to produce insulin: eventually, your body may stop producing (diabetes type 1) or stop responding to it (diabetes type 2).
And so, eating a low-GI diet has many advantages. It can lead to lower body weight, because it controls the appetite and delays the sensation of hunger. It can improve your intake of vitamins and minerals, because you are eating whole instead of refined foods (that are stripped of their nutrients). It can improve glucose and lipid levels in people with diabetes (type 1 and type 2). Finally, it can reduce the chances of insulin resistance (type 2 diabetes).
A day eating low-GI food
Breakfast: Blackberry, banana, soy milk, oat smoothie
Lunch: Pumpkin, spinach, lentil and quesillo salad with cumin and paprika vinaigrette
Snack: Unsalted peanuts
Dinner: Lime and curry marinated pork with quinoa salad
