Insulin is the hormone that allows the glucose from food to enter the body’s cells so that it can be used for energy. Glucose is obtained from carbohydrate-containing foods such as breads, cereals and fruits. In the case of patients with type 2 diabetes (the most common form of diabetes) the glucose accumulates in the blood as the body is resisting the insulin and the pancreas is unable to secrete more insulin in response. It is important to manage diabetes as it can lead to long-term complications such as heart and kidney problems.
Why does diet come into the picture?
There is no one special diet for managing diabetes. However, the amount and, more importantly, the type of carbohydrates consumed influence the blood glucose levels in people with diabetes. In addition, the overall food choices you make (e.g. the amount of saturated fat in your diet) influence calories, energy balance and therefore body weight. Particularly, weight concentrated around the abdomen is a predisposition to diabetes. A possible explanation to this is that adipose tissue is metabolically active and releases inflammatory chemicals in the blood. This is said to cause insulin resistance.
Why is it beneficial to see a dietitian?
Dietitians provide nutrition education to diabetic patients to help them with healthy food choices and low GI carbohydrate choices . Dietitians assist patients in making dietary changes that not only help with blood sugar control, but also help manage their weight. As previously mentioned, weight is a major factor in the progression of diabetes. However, even a modest weight loss of 5% has shown to improve glycaemic control and may even avoid the need for glucose-lowering medications. In the pre-diabetic stage a 5-10% weight loss can prevent diabetes altogether. The pre-diabetic stage is characterised by abnormally high blood glucose levels but is not at a stage where it can be diagnosed as diabetes.
What type of carbohydrates should I be eating?
Carbohydrates are important as they are our main source of energy. However, one should choose low GI carbohydrates. GI refers to the glycaemic index which is a way of ranking carbohydrate-containing foods (from 0-100) based on whether they raise blood sugar levels a lot, moderately or a little. Low GI carbohydrate foods get digested slowly in the blood and hence prevent ‘spikes’ in blood sugar levels. In addition, because they get absorbed slowly, they keep you full for longer and therefore control your appetite. Examples of low GI carbohydrates include wholegrain breads and cereals, oats and fruits. On the other hand, foods with a high GI value get absorbed very quickly and cause an instant rise in blood sugar levels. Examples of high GI foods refer to refined foods such as white bread, cakes, pastries and fruit juice.
What does dietary management of diabetes involve?
1. Eating regular meals and spreading low GI carbohydrates across the day
2. Consuming low GI carbohydrates
Choosing the right type of carbohydrate is a sustainable method of diabetes management. For example, swapping corn flakes with traditional porridge, choosing wholegrain bread instead of white bread, and choosing basmati rice over jasmine rice.
3. Regulating the amount of carbohydrates you’re consuming
The general guideline is to have about 2-3 servings of carbohydrates a day with main meals and one serve with snacks. However, this needs to be individualised and can be worked out with the help of an accredited practising dietitian.
This includes filling half a plate with vegetables, a quarter with grain and starchy vegetables, and another with meat or alternative protein.
5. Choosing healthy fats
Healthy fats such as olive oil, nuts, avocado and oily fish like salmon and tuna are protective against heart disease. Choosing healthy fats is important as diabetes is strongly associated with the risk of heart disease.
Foods to avoid
Foods that should be limited for people with type 2 diabetes include:
- Sweet foods and foods with added sugar, such as fruit juice and sugar-sweetened beverages
- Saturated fats, including full-fat dairy products, processed meats like bacon and salami, and snack foods like chips and baked goods
General macro-nutrient distribution
Your carbohydrate intake should be about 45-60% of the diet and it should consist of predominantly high-fibre, low-GI carbohydrates. Your fat intake should be about 20-35% of total kilojoules, with less than 10% saturated fats. Trans fats should be limited as much as possible. Protein should make up around 15-20% intake. Your alcohol intake should be moderate (1-2 standard drinks per day) and your sodium level should be below 2300 mg per day.
The importance of carbohydrate intake
If your carbohydrate intake is higher than usual and physical activity isn’t increased, blood glucose levels can rise too high. This is known as hyperglycaemia. Hypoglycaemia is when the blood glucose level drops too low, which happens when food intake is inadequate or a meal is skipped. Hypoglycaemia is of particular concern when a patient is on medications that cause hypos and/or insulin.
Evidence regarding low carbohydrate diets
There is no target carbohydrate intake. However there is evidence to suggest that a calorie-controlled, low carbohydrate diet which is high in unsaturated fat and lower in saturated fat, as part of a lifestyle modification program, along with regular exercise can:
- Achieve considerable weight loss
- Control glucose better
- Reduce the need for diabetes medication
However, these benefits may be attributed to weight loss achieved through reduction in overall calories and do not necessarily require a reduction in carbohydrates.
What about the ketogenic diet?
This diet allows for very small amounts of carbohydrates (less than 50g of carbohydrates in a day) which causes the body to move from its preferred fuel — glucose obtained from carbohydrates — to fats, resulting in fat loss. This process is known as ketosis. Although the ketogenic diet can achieve weight loss through the metabolism of fatty acids, suppression of hunger, and reduction in Hba1c because of lowered carbohydrate intake, it is important to note that there are side effects.
There is a hypoglycaemia risk for patients on insulin or medicines that can lead to hypoglycaemia. The inadequate fibre intake on the ketogenic diet in the long term can lead to constipation and even cancer of the colon.
Contact us for results focused nutritional advice
This article was written by our dietitian and nutritionist Juhi Bhambhaney. If you have any questions regarding health and nutrition, make an appointment with one of our dietitians. We‘ll provide you with a simple and effective routine targeted to your concerns. Contact us today.