What is the Glycemic Index and Glycemic Load?
The subject of today’s blog is the Glycemic Index and Glycemic Load, which are of interest to anyone looking to avoid spikes in blood sugar levels, in particular those with diabetes or who want to lose weight.
Understanding the Glycemic Index and Glycemic Load can also be helpful when deciding which Macronutrients (food and drink) to consume before and after exercise – whether you are playing sport, taking part in a fitness class or following an exercise programme with a personal trainer.
What is the Glycemic Index?
Often shortened to GI, the Glycemic Index is a way of measuring how carbohydrate in food affects blood glucose levels, giving each food stuff a value from 0 to 100.
Foods with the lowest scores will have little effect on blood glucose levels while sugar receives the top value of 100. The GI of food will be affected by its starch, fibre, fat and protein content.
What is Glycemic Load?
Glycemic Load gives more detailed information on how much glucose is delivered by the food you are eating and should be assessed in conjunction with GI. Food that is high GI but low in carbohydrate might only deliver a low Glycemic Load.
What are the benefits of eating low GI carbohydrates?
Low GI foodstuffs can help you manage your weight as they leave you feeling full for longer, controlling your appetite.
This is because they take longer to digest and are absorbed into the bloodstream less quickly than high GI foods. Your blood glucose levels will rise more slowly as a result, which is less likely to cause spikes in the production of insulin.
Athletes may consume low GI foods before competing for sustained energy or use high GI foods for bursts of energy or after competing to help recovery.
What kind of foods have a low or high GI?
Food rich in fibre and fat tends to have a lower GI, including kidney beans, peas and lentils, fresh or dried fruit, high-fibre bran and la range of vegetables.
Processed food usually has a high GI rating, as does bread, white rice, potatoes, conserves and energy drinks. These foods are often linked to 'The Benefits of Reducing Sugar Intake'.
However, Glycemic Load is also important to take into account. Carrots have a high glycemic load as they contain a large amount of sugar, however, the sugar is predoinaanlty low GI meaning they have little effect on blood sugar levels.
It also shouldn’t be presumed that lower GI foods are automatically healthier as they may be high in fat; for example, crisps have a lower GI than boiled potatoes.
Why is this important for diabetics?
People with Obesity and Diabetes generally benefit from avoiding unexpected spikes in blood sugar, so may want to monitor the Glycemic Load of the food they eat. However, generally eating healthily and keeping to the right weight are as important, especially for those with Type 2 diabetes.
Diabetics, in particular those with Type 1 diabetes, should be aware of how to avoid hypoglycaemia, or very low blood sugar, as this can cause a range of symptoms from feeling lightheaded and irritable at one end of the scale, to seizures and falling into a coma at the other. If this happens, it’s best to consume blood glucose boosting food or drink that doesn’t contain fat, for example glucose tablets, fruit juice or raisins.
While following a low GI diet can help with weight loss and benefit those with diabetes, it’s important to keep an eye on the bigger picture and to be aware of the other pros and cons of eating certain foods, in particular their carbohydrate and fat content. Athletes and those taking part in sport or exercising in a gym environment may also benefit from consuming either low or high GI foods at different periods of their training.
However, as not all GI foods are healthy and some high GI foods that are low in carbohydrate can be beneficial, it’s important to consult a dietician or medical professional before embarking on a particular diet.