Low GI Diet
What exactly is the Glycaemic Index (GI)?
In 1981, professor of nutrition Dr David Jenkins was looking at how different carbohydrate-rich foods affected blood sugar levels in people with diabetes and discovered that, contrary to popular belief, many starchy foods affected blood sugar levels quite dramatically, while some sugary foods had little effect. From his research, he developed a scale called the Glycaemic Index, which quite simply ranked foods based on the effect they had on blood sugar levels.
So what’s the link with weight loss?
The theory behind diets based on the Glycaemic Index is that foods with a low GI value slowly release sugar into the blood, providing you with a steady supply of energy, leaving you feeling satisfied longer so that you’re less likely to snack. In contrast, foods with a high GI value cause a rapid – but short-lived – rise in blood sugar. This leaves you lacking in energy and feeling hungry within a short time, with the result that you end up reaching for a snack. If this pattern is frequently repeated, you’re likely to gain weight as a result of constantly overeating.
Glycaemic Index of foods
There are many books and websites that list the GI index for different foods. Food values may vary slightly depending on the source, but in general, they should all be roughly the same.
Many lists divide the foods into low, medium/moderate and high categories. Foods in the low category usually have a GI value of 55 or less; in the medium category, a GI value of 56 to 69; and in the high category, a GI of 70 or more. This Glycaemic Index Table gives examples of the GI values of food. You might be surprised by some of the foods included in the low and high categories – for example, ‘healthy’ rice cakes and branflakes actually have a high GI whereas salted peanuts and milk chocolate have a low GI value!
How do GI diets work?
Diets based on GI index simply encourage you to eat plenty of foods with a low GI value and avoid those with a high GI value. This helps to prevent swings in blood sugar, helping you feel fuller for longer. However, most GI diets also recommend cutting down on fat, especially saturates. This means many of the foods which have a low GI value but are high in fat – whole milk, crisps and chocolate, for example – are still limited.
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.
So what happens when I eat a meal?
GI index charts only identify the effect different foods have on bloods sugar levels when they are eaten on their own and, consequently, many nutritionists believe this is one of the main problems with GI diets. Basically, when you eat a mixture of foods together as in a meal, the GI value of that whole meal changes. As a guideline though, the more low GI foods you include in a meal, the lower the overall GI value of that meal will be.
Are there any cons to the GI diet?
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.
What do the experts think?
In general, most nutritionists and dieticians are supportive of the basic principles of the GI diet. They do, however, believe that you shouldn’t get too hung up about avoiding all high GI foods because when foods are eaten together in a meal, that meal can have a very different GI value to the individual foods it contains.
How much weight can I expect to lose?
Most GI diets suggest you will lose around 1-2lb a week, possibly with a slightly greater loss in the first few weeks when your body loses water as well as fat. This follows the guidelines recommended by nutrition experts.
For more information, please visit the official website
The Low GI Diet from my experience
Sustainability: This diet meant that I could have no rice with my curry, no chips with my ‘fish and chips’ and no crips or carbohydrate rich foods whatsoever. At first I found it hard, at lunch I would go to make a sandwich and have to stop myself, because as I was making it, it would slowly sink in that bread was carbohydrate. In the mornings I would wake up prepared for a regular bowl of “Co-Co pops”, just to find I wasn’t allowed these either. One of the most challenging aspects of this diet for me was that I couldn’t consume anything that filled me up, so I had to find substitutes for these foods. Instead of cereals in the mornings I would make myself an omelet with chopped onion and feta cheese. It was easy to get used to, and I found that I wouldn’t feel I needed to snack until lunch. After a couple of days I learned to ‘love’ salads. On my usual diet, I would have one every now and again. But I had never really tried any dressing before, so this was pretty new for me. I now have 2 personal favourites Blue cheese, and Ranch dressing. At the Super market I spent more time down different isles looking for the freshest produce. Balancing the colours of peppers I bought so I wouldn’t get bored of one colour, sad I know. But it was all these little thing which made it easier for me to stick to the diet. I bought peanuts (GI value of 20) incase I felt the need to snack, along with Apples (30), Oranges and Pears (35). Instead of drinking Cola and sugary drinks, I had Milk (30) and apple juice (40).
Variety of Foods: Strictly no food with high GI values for the first two weeks. These vary from potatoes to sugar to cereal. The book clearly lines out which food to stay away from, although it is easy to satisfy your needs with the acceptable Low GI foods.
Weight Loss: In the first week of the diet, I recorded a weight loss of 8lb. The second week was slightly less at 6lb. I continued the diet for a further 2 weeks, and lost another 6lb. My total weight loss over 4 weeks was 20lb.
Creativity included in ebook: I found the book very motivational. It set my mind on my goal and nothing else. Without this I think my weight loss would have been very minimal. The book also suggested various exercise routines I could adopt to increase my progress, at my own speed. I feel these were key in my strategy. I would hover the house, just to keep exercising; I don’t think my house has ever been so clean. At the super market I would pack my own bags, instead of letting the shop assistant doing it. After reading the book, my mentality towards dieting totally changed. I was posed on not letting myself become part of the 95% of dieters who fail, and resort to their old habits. With this book I managed to succeed.
For more information, please visit the official website
