GI Diet

Since we were talking about GI diet in class last week, I shall share a little of what I read online; so here goes…

The GI diet is big in the news right now, with businesswomen, first ladies and pop stars all reportedly using this diet to control their weight. Using the Glycaemic Index (GI) as a guide, no food groups are excluded - it takes the best fats, carbohydrates and proteins and offers you a plan that will help you banish cravings, lose weight and improve your health, all while eating satisfying foods. The GI diet is said to be particularly suitable for people with an underactive thyroid, people who have type 2 diabetics, and people who have polycystic ovaries (PCOS). This is because following the plan will help to slow down the release of energy from food and stabilise insulin levels. Following a low GI way of eating will help all of the above conditions. However, we can all benefit from better control of blood sugar and insulin levels – even if we don’t have any of the conditions mentioned.

The theory behind low GI diets is similar to that behind low-carbohydrate diets. That is, high GI foods raise blood sugar and insulin levels and cause weight gain as well as energy highs and lows. If you eat low GI foods, you'll lower your blood sugar and insulin levels, maintain a steady level of energy and you'll lose weight if you need to, or maintain it if you don’t. The GI diet isn’t only suitable for people who want to lose weight - a low GI way of eating can be beneficial for everyone, including people who want to maintain their weight and people wanting to eat healthily. While you can’t work out the GI value of a food, there are easy ways to follow this eating plan. A lot of supermarkets now lable foods if they are low GI and any good GI diet website gives lists of foods that can be used for guidance on what foods are high, medium and low GI.


A breakdown of questions and answers of GI diets/food…


1. How does it works?

The Glycaemic Index runs from 0 to 100 and usually uses glucose - which has a GI value of 100 - as the reference. The effect other foods have on blood sugar levels are then compared with this. In simple terms, the GI index tells us whether a food raises blood sugar levels dramatically, moderately or a little bit. Foods that have only a slow, small effect on blood sugar have a low GI value, while those causing a rapid and massive rise in blood sugar have a high GI value.

2. What affects the GI value of a food?
There are several things. Firstly, the overall nutrient content of a food will affect its GI. For example, fat and protein affect the absorption of carbohydrate. This helps to explain why chocolate, which is high in fat, has a low GI value. It also explains why high-fat crisps have a lower GI value than low-fat jacket potatoes. Whole milk also has a low GI value because it's packed with protein and fat.

How you cook a food, the degree of processing and the ripeness and variety of a fruit, for example, also affect its GI. Even the structure of the carbohydrate itself influences the GI. For example, processed instant oatmeal has a higher GI than traditional rolled oats used to make porridge. This is because, as a result of the processing, the starch in instant oats is more easily exposed to digestive enzymes, causing it to break down and enter the bloodstream more rapidly.

Meanwhile, some foods have low GI values because they are packed with fibre, which acts as a physical barrier, slowing down the absorption of carbohydrate into the blood.

3. Are there any cons to GI diets?
As outlined above, one of the main limitations to GI diets is the fact it's difficult to identify the GI value of a meal. Meanwhile, some foods with a low GI value are also packed with fat and/or salt and contain few nutrients. Chocolate and crisps, for example, are high in fat and contain few vitamins and minerals. Meanwhile, a 50g pack of salted peanuts contains around 5g of salt - that's almost the maximum amount recommended by nutrition experts for good health!

Consequently, it's possible to follow a GI diet that's packed with fat and lacking in many of the nutrients you need to stay healthy. However, most GI diet plans come with advice to cut down on the amount of fat you eat and recommend avoiding many of the high-fat, low GI foods. For example, they recommend choosing skimmed milk over whole milk.