Diabetes is one of the most common chronic diseases in Ireland, estimated to effect over 190,000 people, with a population prevalence of 6.1%.¹ The vast majority (85-90%) have type 2 diabetes. While ageing and genetic susceptibility are significant risk factors, the main triggers for the development of overt type 2 diabetes seem to be lifestyle-related. A wide range of lifestyle factors have been implicated, ranging from early life events to physical inactivity, several dietary attributes and the subsequent development of overweight and obesity.²

Overweight and obesity is one of the strongest factors associated with an increased risk of type 2 diabetes.³ The risk increases with both increasing waist circumference⁴ and body mass index (BMI)⁵ and it is estimated that 80% of patients with type 2 diabetes are overweight or obese.⁶

In fact, the term ‘diabesity’ is considered a more apt term as it reflects both aetiology and clinical presentation; some authors have called for its adoption to promote the recognition of excess body fatness as the major driver underlying the development of type 2 diabetes.³

Overweight and obesity are also independently associated with an increased risk of a number of comorbidities commonly found alongside type 2 diabetes, including hypertension and coronary artery disease.⁷

Weight loss and type 2 diabetes

The key message for patients however is a positive one; even modest weight loss can have a dramatic effect on type 2 diabetes. We know from the Finnish Diabetes Prevention Study that the risk of developing diabetes was reduced by up to 58% in people with impaired glucose tolerance who implemented lifestyle change and lost approximately 3.5kg.⁸

Moderate weight loss (5% of body weight) can improve insulin action, decrease fasting blood glucose concentrations, and reduce the need for diabetes medications.⁹

Weight loss has other important additional health benefits in patients with diabetes, including decreased blood pressure, improved serum lipid concentrations (decreases in serum triglycerides, total cholesterol, and LDL and increases in HDL) and reduced serum markers of inflammation.⁹

It’s important to remember that lifestyle change is as essential throughout the lifespan of type 2 diabetes as it is at diagnosis. Promoting weight loss, or at least avoiding weight gain, should remain an underlying theme throughout the management of type 2 diabetes, even after medications are started or increased.¹⁰

It is worth bearing in mind that most trials proving the efficacy of diabetes and weight loss medications include a substantial element of lifestyle counselling which undoubtedly augments the headline results.¹¹

Supporting patients to lose weight

Losing weight isn’t easy. For most people it means making a concerted effort to change their diet and increase activity levels. It’s important to stress however that here, again, relatively small changes can have a dramatic effect on weight. 

A 500-1,000kcal deficit per day will result in a loss of  approximately 1-2lbs (~0.5-1kg) per week and an average total weight loss of approximately 8% after six months.⁹

Considering recent research showed that the average pizza in Ireland contains in excess of 1,000kcal,¹² that deficit may not be as difficult to achieve as you’d think. 

Some key, evidence-based, behavioural strategies for achieving weight loss are listed in Table 1 and should be highlighted to all patients with type 2 diabetes trying to achieve weight loss. Food and activity diaries are a very useful first step to help both patients and healthcare professionals to identify goals for change.

Weight maintenance

The key to success with maintaining weight loss is making sustainable changes that fit in with patients’ and their families’ lifestyles. 

The diet industry is worth millions of euro and is frequently a vehicle for the promotion of weight loss products. Unfortunately, we rarely hear as much about non-commercial projects such as the National Weight Control Registry. 

The National Weight Control Registry is a US-based online register of ‘real-life’ successful weight loss maintainers – over 10,000 people who have lost at least 13.6kg (30lbs) and kept it off for at least one year. The registry research team regularly publish on the reported behaviours^14-16 of these successful ‘maintainers’, and here’s what they do:

• It seems people can be successful working by themselves or in groups with other people: 45% of people on the registry lost the weight on their own while 55% attended a weight loss programme

• Dietary changes are the key to success: 98% of people on the registry maintain a low calorie, low fat diet

• Eating breakfast seems to be particularly important: 78% of people on the registry eat breakfast every day

• Monitoring your weight also seems to be very important: 75% of people on the registry weigh themselves every week

• They’re not sitting on the couch: 62% of people on the registry watch less than 10 hours of TV each week

• They don’t eat out a lot: successful weight maintainers ate out ≤⊇3 times each week

• They’re active: 90% of people on the registry are active for at least one hour each day.

All of these behaviours will benefit, not only long-term weight maintenance, but also the day-to-day clinical management of type 2 diabetes due to their favourable effects on glycaemia. 

The challenge of weight management in type 2 diabetes

Weight management is challenging at the best of times in our increasingly obesogenic environment, as evidenced by our national escalating obesity levels.¹⁷ For people with type 2 diabetes that challenge can be further complicated by the impact of weight-promoting medications, struggling to manage glycaemia during exercise and the presence of comorbidities.

It’s important, however, for healthcare professionals to remember (and to emphasise to patients) that there is good evidence that lifestyle change can improve glycaemic control and attenuate weight gain, even in poorly controlled diabetes requiring multiple medications.^{18, 19}

The recently launched position statement from the American Diabetes Association/European Association for the Study of Diabetes on a patient-centred approach to the management of hyperglycaemia, has stressed that the healthcare team should remain non-judgmental but persistent in re-visiting and encouraging therapeutic lifestyle changes as frequently as necessary with patients.²⁰

Successful weight management is a key therapeutic task for patients throughout the lifecycle of type 2 diabetes. Emphasising the importance of modest, sustained weight loss and offering support to patients in achieving this remains a key challenge for healthcare professionals engaged in the evidence-based management of type 2 diabetes.

For further information on weight management see the following websites:

• www.indi.ie 

• www.weigh2live.eu

• www.getirelandactive.ie

• www.icgp.ie/weightmanagement

Cathy Breen is a senior dietitian in diabetes and weight management at Loughlinstown Hospital, Co Dublin

References

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20. Inzucchi SE, Bergenstal RM, Buse JB, et al. Management of hyperglycaemia in type 2 diabetes: a patient-centered approach. Position statement of the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). Diabetologia. Jun 2012;55(6):1577-1596