1. GI and Heart Disease
Several big studies have linked high-GI foods with heart disease. Harvard researchers tracked the diets of 75,500 healthy women for 10 years. They were aged 38 to 63. The high-GI foods from refined carbs (rather than whole grain carbs) raised the risk of coronary heart disease all by itself. This year, a Dutch study tracked 15,700 adult women for a decade and confirmed this link. High-GI foods are bad for the heart over the long term.
Here’s how these low-GI foods could lower your risk of heart disease:
Lower cholesterol
Good evidence says that low-GI diets significantly reduce cholesterol and triglyceride levels without changing HDL (good) cholesterol levels. In fact, three weeks on such a diet could lower total cholesterol by up to 30%, which is similar to what drugs can do.
Improve insulin sensitivity
High insulin levels are linked to coronary heart disease. In a UK study, 32 patients with this disease kept either a low- or high-GI diet. Those eating the low-GI foods had a much better ability to use insulin than those eating high-GI foods.
Dealing with blood clots
Blood clots can lead to heart attack, stroke, and serious problems in the lungs. High levels of glucose and insulin are linked to a higher risk of clots. In a study, three weeks on a low-GI diet lowered the levels of a chemical that is linked to clots by 54%.
2. GI and Cancer
The link between GI and cancer shows mixed results. In a Canadian study, researchers found that postmenopausal women on high-GI diets had a higher risk of breast cancer — especially those who didn’t exercise much. Yet another study found that premenopausal, and not postmenopausal, women had the greatest risk of breast cancer. Elsewhere, high-GI diets have been linked to a higher risk of colon cancer.
Though the evidence is mixed, the following remains true: a Western diet loaded with refined carbs and low in vegetables, fiber and fruit, plus a sedentary lifestyle, being overweight, and having diabetes or insulin resistance, could be linked to many types of cancer.