Study under review: Effects of High vs Low Glycemic Index of Dietary Carbohydrate on Cardiovascular Disease Risk Factors and Insulin Sensitivity
Foods that contain similar amounts of carbohydrates may differ in the amount and speed at which they raise blood glucose levels. This quality is referred to as the “glycemic index” (GI), and is based upon the blood glucose response (total area under the glucose curve) over two hours to 50 grams of its carbohydrate content, as compared with 50 grams of glucose.
The higher a GI value is, the more the food raises blood sugar in a way similar to pure glucose. Lower GI carbs are those that digest more slowly and don’t raise raise blood glucose to the same degree. However, GI can also be a function of insulin response, and not just a function of carbohydrate digestion or meal composition.
It has become common practice among healthcare professionals to suggest an individual consume “low glycemic index” carbohydrates. However the effects of GI on diabetes and cardiovascular disease (CVD) risk factors have been equivocal in trials, as well as meta-analysis of observational studies.
Further complicating matters is the fact that carbohydrates are not eaten in isolation, but generally as part of mixed meals containing fat, fiber, potassium, polyphenols, and other nutrients that can affect health measures. It is still uncertain what (if any) practical significance there is for manipulating GI in the context of an otherwise healthy diet.
The DASH diet, or Dietary Approaches to Stop Hypertension, is an eating plan recommended for people with hypertension or prehypertension. The DASH diet has been shown to reduce blood pressure, lower risk of coronary heart disease, and improve bone mineral status. The diet puts a big emphasis on increasing fruit and vegetable consumption, controlling sodium intake, and reducing processed food.
The objective of this randomized controlled crossover feeding study was to determine the effects of GI and amount of total dietary carbohydrate in the context of a DASH-type diet, on various risk factors for diabetes and CVD.
Sidebar: A sample guide to the DASH diet
Other Articles in Issue #04 (February 2015)
Mood, dieting, and macros
Transient decrements in mood during energy deficit are independent of dietary protein-to-carbohydrate ratio.
- What If There Were No Dietary Guidelines?
The iPad Hangover
Evening use of light-emitting eReaders negatively affects sleep, circadian timing and next-morning alertness.
Can mice get cancer from steak?
A red meat-derived glycan promotes inflammation and cancer progression.
Sodium phosphate: a potentially underutilized ergogenic aid
Effect of sodium phosphate supplementation on repeated high-intensity cycling efforts.
On the whey to getting lean: one more round of whey vs. soy
Whey supplements more efficiently stimulates protein synthesis during weight loss than does soy protein supplements.
It’s (not) all in your head: how sodium intake affects headaches
Effects of dietary sodium and DASH diet on the occurrence of headaches: results from randomised multicentre DASH-sodium clinical trial.
Diets, fast and slow
The effect of rate of weight loss on long-term weight management: a randomised controlled trial.
- Interview: Ivan Oransky