Diabetes Diet and Exercise

The purpose of managing diet in diabetes is to maintain blood glucose and blood pressure within normal levels and to maintain a lipid and lipoprotein profile that reduces the risk of vascular disease. NICE reviewed this subject in both type 1 and type 2 diabetes and has made some evidence-based recommendations, as follows:

Type 2 diabetes¹

• Dietary advice should be personalised and take on board the individual's needs, cultural and belief, and willingness to make changes.
• Advice should be ongoing and given by a health professional who has expertise in nutrition.
• Available educational programmes should be offered (e.g. DESMOND²).
• Emphasis should be on eating a healthy balanced diet applicable to the general population. Diet should include high-fibre low glycaemic sources of carbohydrate, such as fruit , vegetables, wholegrains and pulses; low fat dairy products and oily fish; and limited intake of saturated and trans fatty acid-containing foods.
• Control of obesity is also important. For people who are overweight , the target should be an initial body weight loss of 5–10%. Lesser degrees of weight loss may still be of benefit and larger degrees may provide additional metabolic advantages.
• Advice concerning carbohydrate and alcohol intake, and meal patterns, should be tailored to the individual.
• Diet should be assessed with a view to reducing hypoglycaemia in patients using insulin secretagogues.
• Limited substitution of sucro-containing foods for other carbohydrates is allowable but excess energy intake should be avoided.
• Foods marketed specifically for diabetics should be avoided.
• Patients admitted to hospital or other institutions should have their meals and snacks planned with a view to providing consistency in carbohydrate content.

Type 1 diabetes³

• Diet should be assessed with a view to reducing hypoglycaemia in insulin-dependent patients.
• The hyperglycaemic effects of different foods should be discussed in the context of the insulin preparation chosen to match the patient's food choices.
• Educational programmes (e.g. DAFNE⁴) should be available to that patients can make an education choice about:
  • The variety of foods they wish to eat
  • Insulin dose changes appropriate to reduce changes in glucose levels when eating different amounts of those foods
  • The type and amount of snacks taken between meals and at bedtime should be discussed in the context of the patient's insulin regime. Those choices may need to be adjusted according to the individual's self-monitoring tests.
• Patients should be made aware of:
  • The effects of different alcohol-containing drinks on blood glucose excursions and calorie intake
  • The use of high calorie and high sugar ‘treats’
  • The use of foods of high glycaemic index

NICE recommends that the nutritional advice given to insulin-dependent patients may need to be modified to take into account patients who:

• Are underweight
• Have eating disorders
• Have hypertension
• Have renal failure

All healthcare professionals providing advice on the management of insulin-dependent diabetes should be prepared to discuss with patients, or arrange a specialist to discuss with them, the following issues:

• Glycaemic index of specific foods
• Body weight, energy balance and obesity management
• Cultural and religious diets, feasts and fasts
• Foods sold as ‘diabetic’
• Sweeteners
• Dietary fibre intake
• Protein intake
• Vitamin and mineral supplements
• Alcohol
• Matching carbohydrate, insulin and physical activity
• Salt intake in hypertension
• Co-morbidities including nephropathy and renal failure, coeliac disease, cystic fibrosis or eating disorders
• Use of peer support groups

Advise snacks only if self-monitoring suggests a need; check particularly if a high insulin analogue dose is needed to correct hyperglycaemia present pre-prandially.

All diabetics⁵

Type 2 diabetes

NICE only gives generalised advice concerning the role of physical exercise in type 2 diabetes.
Guidance can however be found in the St Vincent Declaration and from the American College of Sport Medicine.^5,6Assess and review :

• Activity at work, and in getting to and from the workplace
• Physical activity practice and opportunities in domestic activities and hobbies
• The possibility of formal physical exercise on a regular basis, e.g. :
  • Brisk walking for 30 minutes per day
  • Active swimming for one hour three times a week

Advise that physical exercise :

• Can benefit insulin sensitivity, blood pressure, and blood lipid control
• Should be taken at least every 2-3 days for optimum effect
• May increase the risk of acute and delayed hypoglycaemia

Manage physical exercise using :

• Formal recording of levels of physical activity
• Identification of new exercise opportunities ( see above ), and encouragement to develop these
• Appropriate self-monitoring, additional carbohydrate, and dose adjustment of glucose lowering therapy for those using insulin secretagogues

Warn about:

• Alcohol which may exacerbate the risk of hypoglycaemia after exercise
• The risks of foot damage from exercise (advise low impact exercise)
• The need to consider ischaemic heart disease in those beginning new exercise programmes

Type 1 diabetes

In type 1 diabetes, NICE gives the following guidance:

• Advise that physical activity can reduce enhanced arterial risk in the medium and longer term.
• Give information (if the person chooses to increase physical activity) on:
• Appropriate intensity and frequency of physical activity
• Self-monitoring of changed insulin and/or nutritional needs
• Effect of exercise on blood glucose levels when insulin levels are adequate (risk of hypoglycaemia) or when hypoinsulinaemic (risk of exacerbation of hyperglycaemia)
• Appropriate adjustments of insulin dosage and/or nutritional intake for exercise and for 24 hours afterwards
• Interactions of exercise and alcohol
• Where to find more information