Why low GI matters

Too much refined starch is as bad as refined sugar says Dr Joanna.
Too much refined starch is as bad as refined sugar says Dr Joanna. Photo: Getty Images

Any reasonably informed parent knows that too much added sugar in their child’s diet is not good for them. However too much refined starch in their diets is just as harmful, yet it slips under the radar. The simple thinking of ‘complex carbs are good and sugar is bad’ abounds and leads us to making many incorrect choices when it comes to the best foods for our kids.

The glycaemic index research over the last few decades has shown us that the actual affect of a food on our blood glucose levels is not determined by whether that food is a complex carb (i.e. starch) or a simple sugar. In fact many foods rich in starch cause far bigger effects on blood glucose than many foods containing sugars. But why does any of this matter for kids?

  • Blood glucose fuels the brain and so it follows that rapidly fluctuating blood glucose levels has the potential to negatively impact concentration and cognitive function. This also has the potential to affect their mood, behavior and energy levels.
  • We also know that blood glucose ‘spikes’ that occur after eating high GI meals, damage blood vessels. If this starts during childhood then the accumulation of damage after years of such eating will surely cause cardiovascular problems earlier in life.
  • We are seeing children in their teens being diagnosed with type 2-diabetes. High blood glucose levels means the pancreas has to work hard to produce enough insulin to get glucose out of the blood stream and into cells around the body. A high GI diet therefore requires a lot more insulin to be dealt with than a low GI one with the same amount of carbohydrate. This is not a normal situation and the body does not deal with it well. If it continues the pancreas can simply fail to meet demand.
  • Having too much insulin around, too much of the time, also has the potential to affect fat metabolism, with the end result being more fat being stored and less being burned as fuel. In this way not just the overall kilojoules in the diet, but where they are coming from can affect the risk of obesity and overweight.

The glycaemic index is simply a ranking of foods containing carbohydrates, comparing the effect on blood glucose levels. The good news is that you don’t need to know the actual GI number to follow a low GI diet. All you need to know are the best low GI food choices for your family, and learn the best swaps you can make for the higher GI foods you currently have. Here are my suggestions:

Low GI swaps


*NB You can also use the search engine on www.glycemicindex.com for foods and products. For those with a low GI search for equal to or less than a GI of 55.

A sample low GI day for kids might look like this:

  • Breakfast: porridge with yoghurt, strawberries & slivered almonds
  • Morning tea: oatcakes with cheese
  • Lunch: wholegrain stoneground bread sandwich, an orange & a bag of popcorn
  • Afternoon tea: berry & banana smoothie
  • Dinner: Salmon Pasta, followed by custard with sliced apple

When you consider the low GI foods above, you can see that for the most part they are wholesome, minimally processed foods. To me the GI is really just scientists working out one of the reasons these foods are better for us. But one word of warning: Just because a food has a low GI, doesn’t automatically make it a good choice. The GI is just one tool to help us make better food choices for our families, but there are many other nutritional considerations. Ice-cream has a low GI, but clearly we understand why this is a ‘sometimes’ and not an everyday food. Instead use the GI to help you make the best choices within each of the above categories and above all keep your focus on foods that are as close to how nature intended as possible.