When I was diagnosed with type 1 diabetes, I was given books on low GI eating. I could eat pasta, basmati rice, apples, pears, sweet potatoes, grainy breads, oats – anything with a GI of 55 or lower would have the least impact on my blood sugar levels. It was how I should eat to avoid sudden spikes in my sugar levels, according to my diabetes educator, dietitian, GP, and endocrinologist. Watermelon, corn flakes, mashed potato, rice cakes – anything rated as high GI – was a no-no. Anything in the middle – couscous, pineapple, popcorn – was still OK in moderation. So, armed with GI tables and low GI recipe books, I went on my way and ate accordingly.
What is GI?
The glycemic index is basically a measurement of the rate of absorption of glucose into the bloodstream. It is a scale from 0 to 100, and is broken into 3 categories – high (70 or more), medium (56 to 69), and low (55 and below). White bread, corn flakes, and sweets are among those rated as high GI as they raise blood sugar levels more quickly because the glucose in these foods is more rapidly absorbed in the blood. Foods on the lower end of the scale, such as beans, basmati rice and al dente pasta, have a slower release of glucose into the blood, making them more ideal for diabetics than higher GI foods.
Now, 9 years on, with years of up and down trial and error of different foods and trying various ways of eating, I have had my fair share of low GI. I admit that eating a sweet potato is better on my levels than eating fluffy white potatoes, grainy sourdough bread is better than crumpets and white bread, and oats are better than corn flakes. So, low GI has some merit in my books. It has helped with controlling my blood sugar levels, to an extent.
But the amount of low GI carbs I was eating was not. There are times when I have eaten sweet potatoes, baked beans. sourdough toast, or lentil soup – all classed as low GI – and my levels have skyrocketed. Low Gi is great in theory, and it does provide a good basis for knowing which carbs to eat and which ones to avoid in order to avoid massive spikes in blood glucose levels. I haven’t eaten corn flakes or rice cakes for years, because I know from experience that they have the same effect as eating sweets for me. But it is also important to factor the amount of low GI foods you are eating. Eating a big sourdough pizza is difficult to manage. Having a small piece of grainy bread with your eggs is easier to manage. Having just an omelette is even easier still.
I was never told to lower my carb intake by dietitians, nutritionists, endocrinologists, GPs, or diabetes educators. When I had an HbA1c test result of more than 9, my diabetes educator was visibly angry at me for not being more careful. But I didn’t know what to do. I was following the advice they gave me. When I confessed to the dietitian and nutritionist that I thought my eating habits were what was affecting my high levels (sometimes rising up to 25 mm/L post-meal), I was told I could still eat anything I wanted, as long as I carb counted correctly, and stick to low GI foods. Keep having basmati rice, wholegrain pasta, grainy breads, low GI fruits.
It wasn’t until I spoke to other diabetic friends that I realised I could gain better control of my levels by eating lower carb. It was also speaking to them that I reaslised GI affects people differently. Some friends said they couldn’t go near pineapple because it had a high GI affect on their levels; other friends admitted to eating watermelon, which is a high GI food, and said it didn’t spike their levels.
I read some books, including Dr. Bernstein’s Diabetic Solution and The Diabetic Diet, and put some theories into practice. Eating low carb, with the concessional small portion of low GI carbs, has proven to be the diet that works best for managing my sugar levels. It is not easy to maintain healthy blood sugar levels when you are eating carbs all the time. Counting carbs at every meal is not easy or always possible. Opting for lower carb foods, and opting for small quantities of low GI foods, seems to work best for me.
But, taking these ideas to a dietitian does not get such a positive response. Low carb is still controversial. At a type 1 diabetes talk, run by JDRF that I attended in November 2015 in London, the dietitian who was giving a presentation about food, exercise and diet for type 1 diabetics did not want to hear about low carb diets and the positive effects it had proven for many people in the audience. These people swore that low carb had improved their overall blood sugar control, lowered their HbA1c levels, and gave them ideal triglycerides and cholesterol levels. She basically shunned the evidence, said that no trials had been done therefore there was no real evidence, and kept promoting the traditional food pyramid of a high carb low fat diet, even for diabetics who struggle every day with keeping levels low when eating a high carb diet.
Dr. Bernstein, a long advocate of the low-carb diet for diabetics, shuns the glycemic index, saying that it is not accurate enough to provide stable sugar levels. There are so many variables: How cooked the food is (Do you boil peas for 5 minutes or 20 minutes? What happens if you overcook the pasta by a couple of minutes?); How processed it is (Is it mashed, juiced, pureed, or eaten whole? How refined or course is the flour in that bread?); How ripe or unripe it is (How green is that banana? Were those plums picked early or late?). How the testing was done and who was tested (Was it tested on diabetics or non-diabetics?), and what the outcomes show (Does the effect of GI differ from person to person?) are all questionable variables. Every body is different, and we absorb different foods at different rates depending on the person, so how a sweet potato affects my blood glucose levels is going to be different to how it affects yours.
Note that.a lot of GI tables also differ. Some say bananas are high, some say they are medium, some say that bananas are low if they are unripe. There are a myriad of wholegrain breads available – so which one is 55 and which one is 68? Pureeing a vegetable will impact its absorption. Cooking a vegetable soup for an hour and a half compared to half an hour will also make a difference. That’s because every bit of food, and every person, and every test, has its variables.
So, what do we take from this? Our aims as diabetics is to have a ‘normal’ HbA1c of below 7 – in fact, if we talk of ‘normal’, it should be closer to 5. That means having mean sugar levels of about 5 or 6, ranging between 4 and 8, never going above 10, all the time. This is incredibly tricky, particularly if you are eating carbs, whether they are low GI or not. Low GI makes it easier to not have large spikes in the teens and 20s (which, believe me, happens, sometimes more often than you would hope). But, eating a portion of pasta, rice, or wholewheat bread, even if they are low GI, can have a roller coaster impact on your levels if you don’t get the carb counting 100% correct and if you miscalculate things like how ripe the fruit is, how pureed the vegetable is, and how processed the bread is.
No matter how much I tried to count carbs and get my portions right, I have still suffered from unstable sugar levels for years. I now opt for lower carb, and when I have some carb, I make sure it is a small portion and try to go low GI on foods I have tried and tested myself, but I don’t invest everything in GI tables.