Glycemic index diet: What's behind the claims

The "glycemic index diet" or "GI diet" or "low glycemic diet" is more a way of eating rather than a diet. Originally developed as a tool to help diabetics manage blood sugar, the glycemic index diet has found its way into the mainstream weight loss market.

What is GI (Glycemic Index)?

Not all carbohydrate foods are created equal, in fact they behave quite differently in our bodies. The glycemic index or GI diet is an eating plan based on how foods affect your blood sugar level.

The glycemic index is a system of assigning a number to carbohydrate-containing foods according to how much each food increases blood sugar. The glycemic index itself is not a diet plan but one of various tools — such as calorie counting or carbohydrate counting — for guiding food choices.

The term "glycemic index diet" usually refers to a specific diet plan that uses the index as the primary or only guide for meal planning. Unlike some other plans, a glycemic index diet doesn't necessarily specify portion sizes or the optimal number of calories, carbohydrates, or fats for weight loss or weight maintenance.

GI values are generally divided into three categories:

• Low GI: 1 to 55 -  Green vegetables, most fruits, raw carrots, kidney beans, chickpeas, lentils, and bran breakfast cereals.
• Medium GI: 56 to 69 - Sweet corn, bananas, raw pineapple, raisins, oat breakfast cereals, and multigrain, oat bran, or rye bread.
• High GI: 70 and higher - White rice, white bread, and potatoes.

For example, raw carrots have a GI value of 35. This means that if you eat enough carrots to consume 50 g of digestible carbohydrates (sugars and starches), your blood glucose level after eating the carrots will be 35% of the blood glucose level after eating 50 g of pure glucose.

Comparing these values, therefore, can help guide healthier food choices.

"Good" vs. "Bad" Carbohydrates

In the simplest of terms, a low-glycemic diet is generally high in good carbohydrates (like vegetables and whole grains) and low in bad ones (like chocolate chip cookies). Lean proteins and healthy fats round out the rest. It's the middle ground between diets that are packed with protein, which promise satiety, and those loaded with fiber, which are the most nutritious. But that's not the whole story. The GI diet plan is one of the most complicated ever to hit the bookstore shelves. There are many versions of the same diet. Some allow carrots, some don't. Some say bananas are okay, others say they're not. What most experts do agree on, however, is that following one may not do any harm and can even confer health benefits beyond basic weight loss. So, before you try one, here's what you need to know:

What you should eat

• Use breakfast cereals based on oats, barley, and bran.
• Use unrefined breads as they have higher amounts of fiber and a lower GI value than white breads.
• Reduce the amount of potatoes you eat.
• Enjoy all other types of fruit and vegetables as they tend to have a low glycemic index .This is because they contain very little carbohydrate per serving. This also applies to carrots, which were originally and incorrectly reported as having a high GI.
• Eat plenty of salad vegetables with a vinaigrette (a mixture of vinegar and oil flavored with herbs and spices) dressing.