The proportion of energy derived from carbohydrate is related to the level of fat intake. Recommendations in the past have tended to be narrow and precise with regard to fat and carbohydrate intake. Although good diabetes control can be achieved with a range of carbohydrate intake (45 – 60%), it can be difficult to maintain a high-carbohydrate/low-fat balance in practical terms.
The current emphasis is on a more flexible approach dependent upon the individual’s lifestyle, habits and diabetes management.
To minimise the risk of hypertriglyceridaemia and an associated increased risk for cardiovascular disease, high-carbohydrate diets for people with diabetes should incorporate a high intake of soluble fibre and resistant starch.
In cases where a lower carbohydrate intake is optimal for control and lifestyle, intake of energy from monounsaturated fat can be increased, as long as calorie control is monitored.
The glycaemic index (GI), see “The Role of Carbohydrate in the Management of Diabetes” section, was proposed as a method to guide food selection in the early 1980s by Jenkins and colleagues. It is based on the assessment of carbohydrate foods in terms of glycaemic response compared to the same amount of a standard carbohydrate-containing food (usually bread or glucose).
The GI of a food is determined by a number of factors, including the rate of digestion and absorption. The soluble fibre content as well as the structure of the food and other meals and foods consumed as part of the overall diet are all significant influences on the glycaemic index of a particular food.
Dietary fibre or non-starch polysaccharides may broadly be classed as soluble fibre (gums, gels and pectins) and insoluble fibre (cellulose and lignin).
There is epidemiological evidence that low intakes of insoluble fibre are associated with an increased risk of Type 2 diabetes. In general, the benefits of insoluble fibre are limited to promoting healthy gut functioning.
The intake of soluble fibre is however beneficial to glycaemic and lipid control.