Current dietary trends and people with diabetes

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1 Current dietary trends and people with diabetes Kim Duggan-Larkin, BSc, BA, Masters Nutr & Diet, APD Jane Karpavicius, B Nut&Diet, BAppSc (FoodSc&Nut), APD Let s face it, fad diets are not going to go away. The latest diet craze is regularly featured in the media promising weight loss and better health and they have many, many followers, including people with diabetes. For someone with diabetes these diets may pose some risk, particularly if they are taking insulin or a sulphonylurea. Here we discuss three popular diets, their health benefits and their potential impact on someone with diabetes. The 5:2 diet What is it? The 5:2 diet is the most popular of a group of diets involving intermittent fasting or intermittent energy restriction. This is the practice of periodically restricting energy for weight loss. It usually involves severe energy restriction for a period of about 24 hours several times per week. On the 5:2 diet participants severely restrict their energy intake on two (usually non-consecutive) days per week. On these fasting days, energy is restricted to about a quarter of normal energy intake which amounts to about calories per day. This is typically achieved by restricting carbohydrate foods, and consuming small amounts of high protein and high fibre foods to assist with satiety such as low carbohydrate vegetables, low fat dairy foods, fish, eggs, and meat. The remaining five days of the week, participants eat normally i.e. consume adequate calories to meet their energy requirements. This has at times been interpreted as eat whatever you want on the 5 non-fasting days. This may result in overeating, and reduce any benefits they may get from their fasting days. In one study however, it was reported that participants actually ate less than normal on their non-fasting days as well 1. Intermittent energy restriction has been shown to produce either the same or slightly greater weight loss than more traditional diets that involve daily energy restriction. One randomised controlled trial involving overweight women without diabetes showed greater improvements in insulin sensitivity and greater loss of body fat compared with a daily energy restriction diet 1. Overall it appears that the benefits may be similar to other calorie-restricted diets, however intermittent fasting may be easier to maintain in the long term, as you do not have to maintain the diet daily. Currently long term studies that test this hypothesis are lacking. There is also a lack of evidence for this diet in people with existing diabetes.

2 Practice points Whilst there is not yet sufficient evidence to indicate that intermittent fasting is a superior dieting approach for people with diabetes, it is a dietary approach that may be adopted by our clients. Most people with diabetes should be able to embark on this diet safely, however for those using insulin or sulphonylureas the following points need to be considered: Individualised advice regarding adjustment of these medications for fasting and nonfasting days, due to the increased risk of hypoglycaemia Frequent blood glucose monitoring is necessary, particularly in the early stages of this diet, to establish a pattern during fasting/non-fasting days, and help inform any medication adjustments required Consider the impact of fasting on other medications that people with diabetes may be taking and seek pharmacy review if necessary There is a risk of hyperglycaemia on non-fasting days if participants overeat on these days Management of hypoglycaemia should be reviewed to ensure appropriate treatment, and participants should be told to stop the fast if a hypo occurs. The diet may not be suitable for those with impaired hypoglycaemia awareness. Advice regarding appropriate timing and type of exercise, as well as how to manage this with medication and food should also be provided. The Paleo diet What is it? Despite its popularity amongst dieters, the paleo diet wasn t designed to be a weight loss diet. The premise of the paleo diet is that our bodies are best suited to the diet on which our genes were made in Paleolithic times and therefore today s diet is the cause for many chronic health issues including cardiovascular disease, obesity and diabetes. So what did our ancestors eat in the Paleolithic era? Well this depended on the climate, season and location of where the hunter-gatherer lived. There was no single paleo diet. However compared to today s diet, the original paleo diet was higher in protein and lower in carbohydrate. It was not a carbohydrate free diet. There is early evidence of grains and legumes being ground, soaked and eaten. The modern paleo diet has many variations; most advocate no grains, legumes, dairy or sugar. Others include chocolate, butter, bacon, chorizo, alcohol and paleo cupcakes - which weren t part of original paleo diets. The fact is, it would be difficult to follow a true paleo diet today. The grains readily available today are highly processed compared to the grains and grasses which were very simply prepared by our ancestors. The meats consumed weren t farmed animals but were wild bison, ostrich and kangaroo (and included the organ meats), which are much leaner and have higher levels

3 of omega 3 fats. A paleo style of eating could be achieved today by consuming more wholegrains, fruit and vegetables, seafood, grass-fed meat and less sugar. The principle of the paleo diet isn t weight loss but rather an attempt to reduce chronic disease. There are several short term studies showing that the paleo diet may improve insulin sensitivity, CVD risk factors and weight in the short term. Jӧnsson found that after 3 months on a paleo diet, people with type 2 diabetes had improved HbA1c, weight, blood pressure and cholesterol 2. Lindeberg found similar results; people with impaired glucose tolerance or type 2 diabetes experienced weight loss and improved glucose tolerance after a 3 month paleo diet 3. Paleo diets are lower in Western processed foods, more specifically energy, carbohydrate, glycaemic load, saturated fat and calcium. Practice Points People following a paleo diet may have reduced carbohydrate intake and insulin or sulphonylurea adjustment may be required A calcium supplement may be required as it can be difficult to meet calcium requirements on a diet free of dairy foods For many people this paleo diet may be much healthier than their usual intake the concept of reduced intake of sugar and less processed foods is supported by dietitians everywhere! A modified paleo diet which includes a small amount of wholegrains, legumes and dairy foods provides a more balanced intake of nutrients and energy. Mediterranean diet What is it? The Mediterranean diet is based on the dietary pattern of the olive growing areas of the Mediterranean in the late 1950s and early 60s. It is often now referred to as a Mediterranean-style diet as the dietary habits in these areas have changed. There is no one Mediterranean diet, as regional variations occurred. However the key features of the Mediterranean diet are: Eating primarily vegetables, legumes, whole grains, fruits, and nuts High consumption of olive oil this is the main fat in the diet Moderate amounts of fish and poultry Limited intake of red meat and dairy foods (moderate yoghurt consumption)

4 Red wine in moderation with accompanying meals The Mediterranean diet has a well-established evidence base for decreasing the risk of cardiovascular disease and some cancers. More recent research has focused on the benefits of this type of dietary pattern on the prevention and management of diabetes. A recent meta-analysis and systematic review concluded that the Mediterranean diet can provide small but significant improvements in HbA1c in people with type 2 diabetes 4. It has also been demonstrated to be effective for achieving weight loss, and improvements in cardiovascular risk markers in people with type 2 diabetes 5. In the large PREDIMED trial, participants were randomised to either a Mediterranean diet or a low fat diet. The results at 4 years demonstrated a reduced incidence of type 2 diabetes of approximately 52% in the Mediterranean group 6. Practice points The Mediterranean diet is a safe long term dietary intervention for people with diabetes It is widely reported to be highly palatable and well-tolerated Adjustment of medication doses may be required if the diet results in reduction of carbohydrate intake and weight loss Many resources are available to help support people to adopt this dietary pattern in Australia including cookbooks and websites. Summary The American Diabetes Association recognises that there is no one diet or eating pattern that is suitable for all people with diabetes dietary advice should be individualised 7. As such, people with diabetes will follow a number of different diets, and diabetes health professionals need to be able to support them to use these diets in a safe way that maximises the benefits they can achieve. We need to keep up to date on the latest trends, and be aware of any potential issues for people with diabetes. For tailored dietary advice, refer to an Accredited Practising Dietitian.

5 1 Harvie, M et al, The effect of intermittent energy and carbohydrate restriction v. daily energy restriction on weight loss and metabolic disease risk markers in overweight women; Br J Nutr, 2013; 110(8): JӧnssonT et al. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study; Cardiovasc Diabetol; 2009; 8:35. 3 Lindeberg S et al. A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease; Diabetologia; 2007; 50: Ajala et al, Systematic review and meta-analysis of different dietary approaches to the management of type 2 diabetes; Am J Clin Nutr; 2013; 97: Estruch et al, Primary prevention of cardiovascular disease with a Mediterranean diet; NEJM; 2013; 368(14): Salas-Salvadó J et al, Reduction in the incidence of type 2-diabetes with the Mediterranean diet: results of the PREDIMED-Reus nutrition intervention randomized trial; Diabetes Care; 2011; 34(1): Evert, A.B et al, Nutrition therapy recommendations for the management of adults with diabetes; Diabetes Care; 2014; 37(suppl 1):S120-S143.