I've written a lot lately with regards to how nutrition can help fuel our workouts, how a good understanding of nutrition can help with weight gain or loss, and now looking at quality ingredients to help keep us fuller for longer to avoid the snacks that we quickly grab but are so often high in sugar, salts or fats. Introducing the Glycemic Index...
The Glycemic Index (GI) is a ranking of foods rich in carbohydrates, based on how quickly they raise our blood sugar levels. It is widely used for people with Type 1 and 2 diabetes (and suggested by doctors for some people that may have high cholesterol levels, or for long term weight management). Foods are ranked from 1-100; the lower the ranking, the slower your blood sugar levels will rise as energy is slowly released. Foods with a ranking of 55 or less are more slowly digested and absorbed, a ranking of between 56-69 is considered a medium GI food, whilst anything above 70 is considered a high GI food and will cause a quicker spike in blood sugars. For those with diabetes, the glycemic index helps them to understand and control blood glucose levels.
Carbohydrates are required by the body for energy - for both normal bodily functions as well as exercise sessions. You might have heard the term "carb-loading" for runners who load up on carbs prior to a long distance race to provide themselves with lots of slow-release energy throughout their run. This is the same sort of concept.
Foods such as rolled porridge oats, some fruits, green vegetables, milk, chickpeas, carrots, wholemeal bread etc have a low GI ranking - they'll keep producing energy for you at a slower rate and keep you fuller for longer. In comparison, foods such as soft drinks, white bread, white rice, watermelon, potatoes etc are considered high GI foods, and will cause a very quick spike in your blood sugars but you'll soon feel hungry again.
Although it can be really useful to understand GI foods, you should not plan your entire diet around them - certain foods aren't included within the glycemic index since they are classed more as a protein or fat, and it is very important to include these within your diet to ensure that you are consuming a balanced amount of macro-nutrients and micro-nutrients.The glycemic index also does not consider the way that food is prepared; rolled oats are preferable to instant oats for example, because of how they have been produced, and a green-yellow banana will have far lower GI ranking than a yellow-brown banana... do your research before planning your food! The GI of a food can also sometimes be altered when eating it as part of a meal as opposed to on its own... and just because chocolate has a low GI rating, doesn't mean you should only eat chocolate for the rest of your life (I wish it did!), as you wouldn't consume enough variety within your diet.
I guess what I'm trying to say, is that when meal planning you should include a wide variety of foods to cover all macro and micro-nutrients, but when deciding on carbohydrates there are better or worse choices that you can make. If needing to focus on weight loss, low GI carbs will keep you fuller for longer and lower your chance of snacking. If working out for long periods of time, then low GI foods will also help for slow release energy. If about to compete in a race or event, then a high GI food will help to give you a quick burst of energy. Additionally, you shouldn't just cut out fruits from your diet because they're high GI, since they provide high levels of nutrients and anti-oxidants, both of which are important to all-round health. Everything you consume should be in balance; nutrition, exercise and sleep. Listen to your body - only you know what works best for you.
For more information consider looking at the following pages on the Glycemic Index;
Diabetes UK https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwi607WX0LPqAhWgR0EAHdAeCx8QFjABegQIAhAB&url=http%3A%2F%2Fwww.nnuh.nhs.uk%2Fpublication%2Fdownload%2Fdiabetes-glycaemic-index-dietary-advice-10-0-79&usg=AOvVaw2rTtxii1oKbTWg6-xXI8Ww