Food is made up of various nutrients, vitamins, minerals and water. The nutrients are:
Carbohydrates are the glucose and starches in food. All carbohydrates break down into types of glucose and have a direct effect on a person’s blood glucose level. Foods containing carbohydrate include:
- Breads and cereals
- Starchy vegetables
- Dairy products
- Snack foods
Protein is a nutrient used to build and repair muscles, skin, and cells. Proteins have no direct effect on a person’s blood glucose level. Foods containing protein include:
- Meat, chicken, fish and seafood
Fat is a nutrient that carries vitamins, helps skin health, and adds flavour to food. Fat takes the longest to break down in the body and has no direct effect on a person’s blood glucose level. The different types of fats in food include:
- Trans fats
Polyunsaturated fats and monounsaturated fats are found in vegetable oils and margarines such as olive oil, canola and sunflower, as well as nuts, seeds, avocado and fish. These fats are the healthiest choices.
Saturated fats are found in animal foods such as fatty meats, butter, lard, full-fat dairy products as well as many snack foods and takeaway foods. Trans fats are found in foods such as solid cooking fats, pastries, snack foods and takeaways. Saturated fats and trans fats can raise blood cholesterol levels and should be limited or avoided.
Dietary fat won’t directly affect blood glucose levels, however, a low saturated diet is recommended for long term good health and to reduce the risk of diabetes complications. All fats are high in calories and too much of any type of fat can lead to weight gain.
Vitamins are very small nutrients that help the body work. They help heal cuts, fight infection and keep skin and eyes healthy.
Minerals are nutrients that keep the body strong. Minerals help build and repair bones, control blood pressure, and establish water balance. Water keeps the body hydrated and helps the body get rid of waste. When blood glucose is high, water may be lost in the urine.
Key food choices that a person can make when eating for good health and to manage blood glucose include:
- Eating less fat
- Eating less sugar
- Eating less salt
- Eating more fiber
- Eating regular meals
Three factors affect blood glucose levels:
When meals are eaten
- Eat at least 3 times a day
- Be as consistent as possible
- Do not skip meals
- Eat breakfast
How much is eaten
- Choose appropriate portions
- Include a variety of foods
- Use a small plate and eat slowly
- Eat smaller meals more often instead of one large meal
What is in the food
- Carbohydrates have the greatest effect on blood glucose.
- The body needs carbohydrate, it is the fuel that gives us energy
- Fiber affects how quickly the carbohydrates are digested and enter the blood stream. Eating foods high in fiber slows down the effect of carbohydrates on your blood glucose.
The Plate Method
Healthy eating means choosing a balance of foods from each of the food groups. It is also important to pay attention to portion sizes as a way of managing blood glucose, weight, and cholesterol. The plate method is a way of helping to manage portion sizes and types of food:
- At breakfast, fill 1/4 of the plate with starch, and 1/4 with protein. Add a piece of fruit and a glass of milk.
- At lunch and dinner, fill 1/2 of the plate with non-starchy vegetables, 1/4 with meat and 1/4 with starch. Add a piece of fruit and a glass of milk.
Keep in mind that adding fat adds calories.
Carbohydrates have the greatest effect on blood glucose levels. Counting carbohydrates helps balance the number of carbohydrates eaten with medication, activity, and stress.
Two methods for counting carbohydrates are Choices and Grams.
Count the number of carb choices per meal. The goal is to keep the number about the same from meal to meal. A starting point for women is 3 carb choices per meal and 4 carb choices per meal for men. Counting carbohydrate grams. Count the number of grams of carbohydrate per food choice. Counting carbohydrate grams is more precise, and a person can match their pre-meal insulin to the amount of carbohydrates they eat. It may be more work, but it gives more flexibility. A starting point for women is 45 grams of carb per meal, and 60 grams of carb per meal for men.
If you want to learn more about counting carbohydrates consult a dietitian or diabetes educator.
The Glycaemic Index
Carbohydrates are not all the same – some raise blood glucose more quickly than others. The Glycaemic Index (GI) system classifies carbohydrates according to how fast they raise blood glucose levels in the blood. In simple terms, a food with a high GI raises blood glucose faster than a food with a low GI.
A number of factors influence the effect of carbohydrate foods on blood glucose after they are digested. These include the type of food, how it is prepared and cooked, cooking time, fiber content, fat content and what food is taken at the same time.
GI is measured on a scale from 1 to 100 and classifies carbohydrate foods into three general categories:
- High: foods that cause a rapid rise in blood glucose levels and have a GI value of 70 or more.
- Intermediate: foods that cause a medium rise in blood glucose and have a GI value between 55 and 69.
- Low: foods that cause a slower rise in blood glucose and have a GI value of 54 or less.
Things to consider when using the Glycaemic Index:
- A food with a low GI value may not be healthier than food with a high GI. Many nutritious foods have a higher GI than foods with little nutritional value. Therefore it is important to consider the overall nutritional content of a food rather than just its GI score.
- The GI does not measure the amount of carbohydrate that a person typically eats. Portion sizes remain important for managing blood glucose and for maintaining or losing weight.
- The GI of a food may change when is eaten with other foods.
Reading food labels
In some countries food manufacturers are required to put labels on all packaged foods letting you know what is in the product. Check the food you buy to see if there is a food or nutrient label.
When looking at a label, be sure to look first at the serving size. All the information is related to the serving size. And serving sizes will differ per product (some cereals may have a serving size of 1/4 cup, or 1/2 cup or 3/4 cup). How much is on your plate?
- Serving size
- Fat content and types of fat
- Sodium content
- Total Carbohydrate
- Dietary fiber
- Other nutrients
Of these, only serving size, total carbohydrate and dietary fiber directly affect blood glucose. Fiber is a form of carbohydrate that has no effect on blood glucose levels. It can be subtracted from the total carbohydrate.