Diet & lifestyle management strategies for diabetes
Overall aim of treatment = optimise blood glucose control to reduce the risk of short and long-term complications.
Maintain a healthy weight
Carrying excess weight (particularly around the middle) = insulin resistance.
Therefore, weight loss will help insulin to work better and be more efficient at lowering blood glucose. There are a number of ways we can tell if we need to lose weight (BMI, waist measurement, or simply clothes feeling a bit tighter). Research has shown clinical benefits with a modest weight loss of 5-10%, including a significant reduction in HbA1c, blood pressure, total cholesterol and a better balance between the ‘good’ and ‘bad’ components of cholesterol (15) so it is reasonable to suggest this as a good starting point. Achieving small realistic goals tends to be more sustainable and motivating.
Optimise blood glucose control
This isn’t about avoiding all foods that affect blood glucose, i.e. carbohydrates. This is about ensuring an optimal balance and spread of foods across the day to improve blood glucose regulation.
Maintain a healthy heart
We know that diabetes increases the risk of cardiovascular disease so it is important to optimise diet to reduce all other risk factors, such as cholesterol and blood pressure.
Keep physically active
Physical activity helps to increase energy expenditure and is therefore beneficial for those trying to manage their weight. It also helps to reduce blood glucose, as the muscles become more insulin sensitive (16 &17). Don’t forget all the additional benefits for heart health, mood, and muscle and bone strength for maintaining good mobility too!
Watch what you eat
Contrary to many people’s beliefs, there is no such thing as a “diet for diabetes”. Recommendations around what you should or shouldn’t eat are the same as for those without diabetes – following a healthy balanced diet.
- Avoid buying foods marketed for people with diabetes– Lots of people are tempted by the idea of eating these foods such as “sugar-free” chocolate/ confectionary. Unfortunately, they often come with the warning that excessive consumption may cause a laxative effect (due to containing sweeteners e.g. sorbitol/xylitol etc). Products tend to be expensive, higher in fat (to add flavour) and there is no evidence to support their use. Unless you really enjoy a diabetic product, you’re probably better off having a small amount of foods higher in sugar as an occasional treat.
- Eat regular meals – skipping meals often leads to overconsumption at a subsequent mealtime, as the body is craving energy. Eating a larger portion of food will result in a bigger spike in blood glucose compared with a few smaller meals spread out throughout the day. When the body is in starvation mode it will also crave the most concentrated sources of energy, so you are more likely to choose high fat, high sugar foods, which will provide extra calories.
- Eat a moderate portion of starchy carbohydrate with each meal–avoiding carbohydrates may be more detrimental to health. They are an important source of energy, fibre, vitamins and minerals, and wholegrain varieties have also been linked to a reduction in cholesterol levels (18). It is still important to watch the portion size, to prevent excessive spikes in blood glucose levels.
- Glycaemic index (GI) – this can be a complex but potentially helpful tool. GI relates to how quickly a particular carbohydrate-containing food affects blood glucose (see diagram below ). Low GI foods are slowly absorbed, causing a smaller and more gradual peak in blood glucose, whereas high GI foods are quickly absorbed, causing a larger and faster peak in blood glucose.
The effects of low GI & high GI foods on blood glucose levels (19).
- Fruit – many people with diabetes think they need to cut out certain fruit. No fruit is out of bounds! However, watching the portion size is important as fruit is a source of carbohydrate (natural sugar) and can raise blood glucose levels if consumed in large quantities. It is recommended to have no more than 1 portion at a time.
- Fats – fat is the most concentrated source of calories (1g =9 kcal). Extra calories results in weight gain which can increase risk of insulin resistance. It is therefore advisable to stick to a lower fat diet. The type of fat we eat is also important. Too much saturated fat (found in animal products; butter, cream, cheese, meat, baked products; also palm and coconut oil) is linked to increased cholesterol, and particularly LDL cholesterol, which contributes to the furring up of arteries (20). Replacing saturated fat in the diet with more unsaturated fat (fish and plant sources; vegetable/nut/olive oils, nuts & seeds, margarines/spreads) provides a protective effect for the heart by increasing HDL cholesterol which helps to “clear the arteries” (21 &22).
- Omega-3 – this healthy fat isn’t just good for your brain and joints, research has also shown the benefits for heart health (22). Rich sources include oily fish (salmon, mackerel, sardines, fresh but not tinned tuna, etc.); linseeds; flaxseeds; walnuts; rapeseed oil; soya; green leafy vegetables and milk. Current healthy eating guidelines recommend 1 portion of oily fish per week.
- Salt – too much salt in the diet is linked to high blood pressure (23). Unfortunately, it doesn’t matter what form it comes in, be it table/rock or sea salt! The fact is, we consume far too much salt than we need (the average person has more than 8g in the UK), thanks to taste preferences and convenience foods. Current recommendations are to consume no more than 6g per day (1tsp). Some manufacturers are taking steps to reduce salt in their products but the majority of us need to find ways to cut down our salt consumption by revising our cooking methods, flavouring food with other ingredients e.g. herbs and spices.