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Managing weight loss with diabetes

Patricia Miles
Diabetes Specialist Nurse
Royal Bournemouth Hospital

Losing weight is not easy. However, it is even more difficult for someone with diabetes. This is due to the underlying insulin resistance that causes weight gain in people with pre- and existing type 2 diabetes and also because of the medication used to treat diabetes, where reducing food intake may result in  hypoglycaemia.(1,2)
Weight loss should be the first line of treatment for type 2 diabetes, but because we lack the skills or the time or the enthusiasm it is often relegated to advice to "lose weight" without any concrete support.(3) Despite all the information out there about dieting and healthy eating, many people still fail to understand which foods are high in calories. We often treat overweight or obese individuals with diabetes with medication that promotes weight gain and then "tell them off" when they gain weight. Weight gain and increasing insulin resistance leading to further weight gain can be a vicious circle that never results in adequate diabetes control and just increases cardiovascular risk.(4)

Weighing up the maths
On one level, losing weight is a matter of maths. If you eat more calories daily than your body needs, you store it as fat, thereby gaining weight. If you eat the right amount of calories daily, your weight stays stable. If you eat less calories daily than your body needs, you take the remainder from your fat stores, thereby losing weight. My dietetic colleagues tell me you need to eat 3,500 fewer calories to lose 0.45kg (1lb). In a way it doesn't matter how long it takes to achieve this. Even 0.45kg per month would result in 5.4kg (12lb) per year weight loss, and you would only need to reduce your daily calorie intake by around 112 calories to do this (eg, one slice of toast with spread or one packet of crisps or one glass of wine). The trouble is that most people are impatient and want to see rapid results.
The other part of the equation is energy expended. Someone who is sedentary will require far less energy than someone who is active, and they will require even less than someone who takes regular exercise. It may not be possible or practical to advise exercise to someone who has limited mobility or a really hectic life, but all of us could increase our activity levels to some degree. One lady I know started walking for 40 minutes every day and managed to lose 18kg (3st) in 12 months with no change to her diet. Even people who are wheelchair dependent can usually still move some part of their body, and wheelchair exercises are available.
As I'm sure most of us are aware, the highest source of calories in our diet comes from fat (9kcal/g), so reducing fat produces the most rapid results and can be achieved without necessarily reducing the amounts of food eaten. The next highest source of calories is alcohol (7kcal/g), so reducing or stopping alcohol would be the next area to address. After that, protein and carbohydrate foods have equal amounts of energy (4kcal/g), so an assessment of the amounts taken and particularly what is taken with them - for example, sauces and cooking methods - would be the next area to address. If no advice to reduce carbohydrate foods is given, there should be no risk of hypoglycaemia in someone with diabetes.(5)
Unfortunately, it is rarely that simple. People eat for so many different reasons, many of them psychological, and if they are at risk of hypoglycaemia they often overeat to compensate. For weight reduction strategies to be successful, people have to want to make changes.
The majority of people with type 2 diabetes are overweight or obese at diagnosis, and weight loss should be the main thrust of treatment initially.(6) Significant weight loss can delay the need for oral hypoglycaemic agents and insulin or can even cure diabetes in severely obese individuals.(7,8) Weight loss can also improve lipids and blood pressure, again reducing the need for medication. People are often prepared to make significant changes to their diet at the time of diagnosis, so it's a really good time to put effort into supporting these people to lose weight.

Strategies for weight loss
Everyone is different. Some people thrive on a one-to-one approach with regular support, some people prefer to be given the information and then go off and do it themselves. Some people prefer group support; some people need prescriptive diet sheets. There is also a place for commercial slimming groups. In our centre we have used a very low-calorie diet programme successfully for the past seven years, which gives rapid results and enables people with type 2 diabetes to get off insulin and oral agents very quickly.(9)

Maintaining weight loss
Whichever weight loss programme is used, if followed correctly, weight loss will occur, whether over a period of weeks, months or even years. The major difficulty most people have is then maintaining their lower weight long term. Support to maintain the new lower weight is equally as important as support during the weight loss phase. It is really easy to slide back into old eating habits after successful weight loss and end up back where you started or even heavier. That then sets up a "yo-yo" dieting behaviour pattern where the person becomes increasingly despondent about their ability for long-term success. The most successful people I know are those who have a set "buffer" zone for their weight and once they exceed that they do something about it there and then. One lady told me she has lost and regained 3kg (7lb) every year for the past 10 years. What discipline!
Insulin resistance decreases as weight reduces, so insulin requirements whether from injected insulin or sulphonylurea stimulation will be less at the end of successful weight loss. Knowing the right amount by which to reduce these is a skill, and it is better to err on the side of caution than put the patient at risk of hypoglycaemia. One bad hypo can put people off weight loss permanently, and doses can always be put back up a little if glucose levels are running too high. If carbohydrate foods are being restricted or if weight loss is occurring, then proactive reduction is indicated. Metformin or glitazone treatment do not cause hypoglycaemia on their own, so the patient should continue taking these as they are also reducing their insulin resistance. There are two drugs that promote weight loss that can be used in people with diabetes: orlistat (Xenical), which reduces the absorption of dietary fat; and sibutramine (Reductil), which is an appetite suppressant.(10) Two new treatments for diabetes are awaiting licensing: glucagon-like peptide 1 (GLP1) analogues and rimonabant. In addition to lowering glucose levels, these also aid weight loss.

Nurses are often the healthcare professionals patients see the most and therefore are best placed to inform patients on weight loss strategies. Knowledge and confidence in appropriate weight loss strategies together with dose adjustment needed for sulphonylurea and insulin treatment can have a positive effect on a patient's ability to lose weight and maintain it long term.(11) Like diabetes, there is no cure for obesity, just strategies for keeping it under control.



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Diabetes UK

National Obesity Forum

Royal College of Nursing