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The article gave a brief summary of each diet’s key focus (a number of variations exist for three of the four diets) and asked a Diabetes NZ dietitian and Heart Foundation nutrition spokesperson for what they consider to be the pluses and minuses of these diets for people with long-term conditions.

The article gave a thumbs-up to the recent shift in dietary trends away from processed foods towards cooking whole food from scratch, expressed caution about a number of them for people with diabetes and had a general focus on eating a moderate, balanced diet. The article can be viewed by clicking here. 

Amongst the responses – positive, mixed and negative – was that of Professor Grant Schofield of AUT, co-author of What the Fat? Fat’s in, Sugar’s Out. Schofield is a professor of Public Health for AUT, director of AUT’s Human Potential Centre, the country’s leading advocate for the LCHF approach, and has a background in psychology.

Nursing Review offered Schofield and colleagues an opportunity to write an opinion piece in response to the ‘Fad diets’ article. Nursing Review also offered the opportunity to the Heart Foundation, Diabetes NZ and the convenor of Dietitians NZ’s Diabetes Special Interest Group to review and respond to Schofield et al. The resulting four pieces are published here.

OPINION ONE: Grant Schofield et al.

The use of the word ‘fad’ to describe therapeutic diets, some with long histories of clinical usefulness, which enjoy popularity beyond the medical community, is lazy and misleading. This review, despite its commendable focus on real, unprocessed food, contained factual errors with regard to low-carbohydrate, high-fat diets, as well as Paleo and sugar-free diets.

We have summarised only major errors* for comment. The most important correction* for the readership of Nursing Review, is that restricting dietary carbohydrate is an effective option for diabetics.

Myth: Low-carbohydrate, high-fat diets, Paleo, or sugar-free diets can cause hypoglycaemia and ketoacidosis in diabetics

Diabetes medication dosage usually needs to be adjusted downwards on low-carbohydrate diets. However, there are clear advantages to reducing medication when high doses are not needed and stopping it when no longer required.

When blood glucose falls on a ketogenic diet, ketone bodies provide the brain with an alternative fuel source, decreasing the risk of symptomatic hypoglycaemic episodes. A typical result is a reduction of hypoglycaemic events by 80 per cent. Thus diets in which carbohydrate is sufficiently restricted allow better control of blood glucose, often including sustained normal glucose and HbA1c readings in type 1 diabetes, and remission or reversal of diabetes altogether in type 2 diabetes. A 2015 review authored by 25 diabetes experts outlines 12 robust reasons why low-carbohydrate diets should be the first option for diabetes treatment¹.

Drugs that can be reduced or stopped include GSLT2 inhibitors, which have been shown to cause diabetic ketoacidosis in America². Conversely low-carbohydrate diets have never been shown to cause ketoacidosis.

The use of small amounts of glucose to correct hypoglycaemia caused by the unpredictability of insulin dosing still forms part of managing type 1 diabetes, even on a low-carbohydrate diet. This does not mean that there is a requirement for sugar in the diet.

Myths: Low-carbohydrate, high-fat diets cut out fruit; Paleo diets eliminate starchy vegetables; not eating grains is a danger to health. Fruits are not removed on low-carbohydrate diets, rather high-sugar fruits are limited; the degree of restriction depending on an individual’s level of insulin resistance. Paleo diets do not eliminate starchy vegetables, and may allow some dairy products or legumes. Grain avoidance is more than compensated for nutritionally by increased consumption of nuts, seeds, fish and vegetables.

Myth: People will get half the message.
Randomised controlled trials of various diet regimes show low-carbohydrate, high-fat eating is superior in short and medium-term weight loss in free living populations and has reasonable adherence, superior to the low-fat approach, showing that consumers can understand and implement this diet effectively when it is communicated clearly³.

Myth: Saturated fat causes heart disease.
Replacing saturated fat with carbohydrate does not reduce the risk of heart disease, and may increase it. Polyunsaturated fats found in fatty foods are associated with a lower risk of heart disease, whether they replace carbohydrate or saturated fats⁴. This evidence does not suggest that saturated fats are harmful in the context of diets in which fat replaces carbohydrate.

Authors: Professor Grant Schofield, AUT;
Dr Caryn Zinn, registered dietitian and senior lecturer AUT (co-author of What the Fat? Fat’s in, Sugar’s out); and George Henderson, AUT research officer.

REFERENCES

1. Feinman R, Pogozelski W, Astrup A et al. (2015). Dietary carbohydrate restriction as the first approach in diabetes management: Critical review and evidence base. Nutrition 31:1-13 http://dx.doi.org/10.1016/j.nut.2014.06.011
2. FDA Drug Safety Communication: FDA warns that SGLT2 inhibitors for diabetes may result in a serious condition of too much acid in the blood. Retrieved 15 July 2015 from www.fda.gov/Drugs/DrugSafety/ucm446845.htm
3. Nordmann A J, Nordmann A, Briel M et al. (2006). Effects of Low-Carbohydrate vs Low-Fat Diets on Weight Loss and Cardiovascular Risk Factors: A Meta-analysis of Randomised Controlled Trials. Archives of Internal Medicine.166(3):285-293. doi:10.1001/archinte.166.3.285.
4. Jakobsen M, O’Reilly E, Heitmann B et al. (2009). Major types of dietary fat and risk of coronary heart disease: a pooled analysis of 11 cohort studies. American Journal of Clinical Nutrition 89:1425-32. doi: 10.3945/ajcn.2008.27124.

Editor's note:

This opinion piece has been published as submitted. Publication means that Nursing Review is open to publishing counterviews on the issues raised and does not denote agreement that the original article contained errors.

The original article did not say LCHF cut out fruit – it noted that some versions of the diet included people being encouraged to reduce or cut out their fruit intake.

It also did not say that not eating grains was a ‘danger’ but rather said that whole grains have been shown to protect against heart disease. The founder of the Paleo diet concept, Loren Cordain, excludes potatoes, legumes and dairy products. The article noted that a number of variations of the Paleo diet exist, including some involving three non-Paleo meals a week.

OPINION two: Heart Foundation

It is great to see the ‘Fad diets: what do dietitians say about the latest crop?’ article in Nursing Review has been widely distributed, stimulating much interest and debate. After all, it is encouraging to see that so many Kiwis are interested in what they should be eating. Given how divided the current nutrition landscape is, it is no surprise the article has been greeted with hostility by various commentators, even though it noted many positive elements about the diets being discussed.

As we stated in the article, if elements of a new diet (e.g. no-sugar, low-carbohydrate/high-fat (LCHF) or Paleo) help to kick-start, or move someone towards a healthier eating pattern then that is positive. However, we maintain that people do not need to resort to extremes to achieve a cardio-protective dietary pattern. We recommend an approach that works for the individual, is sustainable, and is based on foods shown by the best evidence to reduce the risk of heart disease.

Dietary patterns that support heart health reflect a range of fat, carbohydrate and protein intakes but share common features. These features include: fewer processed foods; plenty of vegetables and fruit; other plant foods such as legumes, intact whole grains, nuts, and healthy plant oils; and usually some fish, poultry, lean meats and reduced-fat dairy¹.

Comments relating to the specific points raised by Schofield et al. follow:

Reducing saturated fat intakes will lower the risk of heart disease: Our comments in the previous article refer to reduction in saturated fat in general, and in fact highlight that a higher total fat intake is acceptable. Evidence shows a reduced risk of heart disease when saturated fat is replaced with polyunsaturated fat^2,3. However, replacing saturated fat with slowly digested, high-fibre, less-refined carbohydrate foods will also provide a reduced risk^4,5. The key is the type of carbohydrate. Replacing saturated fats with highly refined, sugary, carbohydrate-rich foods will offer little benefit.

People will get half the message: Advocates of the LCHF approach have recently promoted cream, butter, and bacon (a heavily processed meat) through major media stories. Sadly, the promotion of healthy cardio-protective fats from foods like nuts, seeds and plant oils, and the fat message in the context of healthy dietary pattern, has been missing from some of these stories.

Confusingly, during a presentation at the 2014 Dietitians NZ National Meeting, those same LCHF advocates highlighted that cream, butter, and bacon were not key fats as part of the LCHF way of eating, whereas the previously mentioned cardio-protective fats were. Therefore, we believe the current LCHF messages being delivered to health professionals and the general population are incomplete, inconsistent and may lead to people making poor dietary choices.

In summary, we continue to emphasise that the quality of carbohydrate and fat in the diet is key. People need to choose an eating pattern that works for them, and that is based on foods that the best available evidence shows reduces the risk of heart disease and diabetes.

Author: Dave Monro is a dietitian and the nutrition spokesman for the Heart Foundation.

REFERENCES

1. Heart Foundation. Dietary patterns and the heart position paper (2014). www.heartfoundation.org.nz/uploads/Dietary_patterns_position_statement_2014.pdf. Accessed 24 July 2015.
2. Jakobsen M, O’Reilly E, Heitmann B et al. (2009). Major types of dietary fat and risk of coronary heart disease: a pooled analysis of 11 cohort studies. American Journal of Clinical Nutrition 89:1425-32. doi: 10.3945/ajcn.2008.27124.
3. Mozaffarian D, Micha R, Wallace S (2010). Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomised controlled trials. PLOS Medicine 7(3):e1000252.
4. Pereira M, O’Reilly E, Augustsson K et al. (2004). Dietary fibre and risk of coronary heart disease: a pooled analysis of cohort studies. Arch Intern Med 2004; 164:370-76. 
5. Stratton I, Alder A, Neil H et al. and the UK Prospective Diabetes Study Group (2000). Association of glycaemia with macrovascular and microvascular complications of type 2 diabetes (UKPDS 35): prospective observational study. British Medical Journal 321:405-12. 

OPINION three: Diabetes NZ

Diabetes NZ offers support and information to help people take charge of their health and live well with their diabetes. We do not provide clinical advice – we complement the services of other healthcare providers. The dietary information we give is in keeping with national and international diabetes dietary guidelines.

Lower carbohydrate diets: People with diabetes currently using insulin or sulphonylurea medication who choose to reduce the carbohydrate in their diets will need advice and guidance from diabetes specialists. This support will help them with carbohydrate counting and medication dose reduction/withdrawal while adapting from their previous eating pattern. Without adequate advice and guidance, the risk of hypoglycaemia is high.

Saturated fat: Diabetes NZ affirms its view that people with diabetes should not have a diet high in saturated fat. Saturated fat has been shown to have a negative impact on heart health and people with diabetes have a well-recognised increased risk of cardiovascular disease. A 2010 study by Otago University researchers found that patients with type 2 diabetes benefited from a reduction in saturated fat as part of a sensible moderate eating pattern¹. These benefits included reductions in HbA1c, weight, and BMI, and some people reduced their diabetes medicine dose.

No-sugar diets: While popular versions of these diets discourage the use of sucrose (table sugar), other sugars such as glucose and dextrose are commonly used in recipes. These sugars are unsuitable for people with diabetes. Diabetes NZ’s overall message is for people with diabetes to reduce their intake of free sugar in all forms. Free sugar is defined by the World Health Organisation and the UN Food and Agriculture Organisation in multiple reports as “all monosaccharides and disaccharides added to foods by the manufacturer, cook, or consumer, plus sugars naturally present in honey, syrups, and fruit juices”^2,3. It is used to distinguish between the sugars that are naturally present in fully unrefined carbohydrates such as brown rice, whole wheat pasta, fruit, etc. and those sugars (or carbohydrates) that have been, to some extent, refined (normally by humans but sometimes by animals, such as the free sugars present in honey).

Author: Submitted on behalf of Diabetes NZ.

REFERENCES

1. Coppell K, Kataoka M, Williams S et al. (2010). Nutritional intervention in patients with type 2 diabetes who are hyperglycaemic despite optimised drug treatment – Lifestyle Over and Above Drugs in Diabetes (LOADD) study: randomised controlled trial, British Medical Journal 341 doi: http://dx.doi.org/10.1136/bmj.c3337
2. Joint WHO/FAO Expert Consultation (2003). WHO Technical Report Series 916 Diet, Nutrition, 
3. and the Prevention of Chronic Diseases. Geneva.

OPINION three: Diabetes NZ

Diabetes NZ offers support and information to help people take charge of their health and live well with their diabetes. We do not provide clinical advice – we complement the services of other healthcare providers. The dietary information we give is in keeping with national and international diabetes dietary guidelines.

Lower carbohydrate diets: People with diabetes currently using insulin or sulphonylurea medication who choose to reduce the carbohydrate in their diets will need advice and guidance from diabetes specialists. This support will help them with carbohydrate counting and medication dose reduction/withdrawal while adapting from their previous eating pattern. Without adequate advice and guidance, the risk of hypoglycaemia is high.

Saturated fat: Diabetes NZ affirms its view that people with diabetes should not have a diet high in saturated fat. Saturated fat has been shown to have a negative impact on heart health and people with diabetes have a well-recognised increased risk of cardiovascular disease. A 2010 study by Otago University researchers found that patients with type 2 diabetes benefited from a reduction in saturated fat as part of a sensible moderate eating pattern¹. These benefits included reductions in HbA1c, weight, and BMI, and some people reduced their diabetes medicine dose.

No-sugar diets: While popular versions of these diets discourage the use of sucrose (table sugar), other sugars such as glucose and dextrose are commonly used in recipes. These sugars are unsuitable for people with diabetes. Diabetes NZ’s overall message is for people with diabetes to reduce their intake of free sugar in all forms. Free sugar is defined by the World Health Organisation and the UN Food and Agriculture Organisation in multiple reports as “all monosaccharides and disaccharides added to foods by the manufacturer, cook, or consumer, plus sugars naturally present in honey, syrups, and fruit juices”^2,3. It is used to distinguish between the sugars that are naturally present in fully unrefined carbohydrates such as brown rice, whole wheat pasta, fruit, etc. and those sugars (or carbohydrates) that have been, to some extent, refined (normally by humans but sometimes by animals, such as the free sugars present in honey).

Author: Submitted on behalf of Diabetes NZ.

REFERENCES

1. Coppell K, Kataoka M, Williams S et al. (2010). Nutritional intervention in patients with type 2 diabetes who are hyperglycaemic despite optimised drug treatment – Lifestyle Over and Above Drugs in Diabetes (LOADD) study: randomised controlled trial, British Medical Journal 341 doi: http://dx.doi.org/10.1136/bmj.c3337
2. Joint WHO/FAO Expert Consultation (2003). WHO Technical Report Series 916 Diet, Nutrition, and the Prevention of Chronic Diseases. Geneva.
3. Moynihan P and Petersen P (2004). Diet, nutrition and the prevention of dental diseases, Public Health Nutrition: 7(1A), 201-226.

OPINION four: Shelley Mitchell, Diabetes Special Interest Group convenor for Dietitians NZ

Nutritional science is constantly evolving and one of the key dietary trends that consistently proves its worth in terms of diabetes and cardiovascular outcomes is the Mediterranean style of eating^1,2,3. This type of diet includes plenty of vegetables, fruits, legumes, wholegrain cereals, plus moderate amounts of heart healthy fats and lean protein.  These principles have been widely incorporated into dietary recommendations for the prevention and management of type 2 diabetes around the world^4,5.

In New Zealand, we have our very own ‘Nine Steps for Heart Healthy Eating’ developed by the Heart Foundation⁶ and featured in the Ministry of Health Primary Care Handbook for cardiovascular disease screening and type 2 diabetes management⁷. I have used the ‘9 Steps’ with a number of people with type 2 diabetes who have gone on to achieve a healthy weight range (BMI 20-25 kg/m2) and a few have even come off their diabetes medications altogether. Others may have stayed on tablets or insulin but are feeling confident that they can stick with their new food plan because it includes a variety of affordable foods they can buy locally.

Naïve to think one diet fits all: It would be naïve to think that any one particular dietary pattern – be it the 5:2 diet, LCHF, or the Paleo approach – is an appropriate solution for the whole population. If only life were that simple! I agree that ‘free sugars’ should be limited⁸, but extreme restriction of wholegrains, legumes, starchy vegetables or fruit is unnecessary and disadvantageous given the role of dietary fibre in disease prevention^4,5. I prefer to support people with diabetes to review whether they are eating the right amount of food for a healthy weight and focus on choosing heart healthy fats, good quality carbohydrates, and abundant non-starchy vegetables. If anything needs to be restricted it would be the heavily processed foods that add many calories but not much in the way of nutrition.

Matching insulin to different diets challenging: Research is still emerging about the impact of high fat and/or high protein meals on postprandial insulin secretion and glycaemic control in adults and children with type 1 diabetes^9,10,11. This presents a challenge for those of us in clinical practice in terms of how we match the right amount and type of insulin to these meals, and challenges the assumption that following a low-carbohydrate diet means people with diabetes will require less insulin.

Personalised advice important: In summary, most experts agree that there are multiple dietary patterns that are beneficial for cardiovascular health and it is important therefore that each person be given personalised advice based on their own needs and food preferences^12,13. It is the position of the American Diabetes Association (ADA) that there is not a ‘one-size-fits-all’ eating pattern for individuals with diabetes¹⁴. Tempting as it might be to be swayed by the latest dietary trends, as clinicians we need to stay grounded in our person-centred practices and consider a number of factors that might impact on the efficacy of any particular dietary pattern as part of our clinical assessment.

Author: Shelley Mitchell NZRD, MSc. is the diabetes specialist dietitian at MidCentral Health and convener for the DSIG of Dietitians NZ.

REFERENCES

1. The PREDIMED Study http://predimed.onmedic.net/eng/Home/tabid/357/Default.aspx accessed 15 Aug 2015.
2. De Logeril M, Salen P, Martin J et al. (1999). Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction: final report of the Lyon Diet Heart Study. Circulation 99: 779-85.
3. Esposito K, Maiorina M, Ceriello A, Giugliano D (2010). Prevention and control of type 2 diabetes by Mediterranean diet: a systematic review. Diabetes Research and Clinical Practice 89: 97-102.
4. Dyson P, Kelly T, Deakin T et al. (2011). Diabetes UK evidence-based nutrition guidelines for the prevention and management of diabetes. Diabetic Medicine 28: 1282-8.
5. Evert A, Boucher J, Cypress M et al. (2014). Nutrition therapy recommendations for the management of adults with diabetes. Diabetes Care 37: S120-S143.
6. The Heart Foundation www.heartfoundation.org.nz.
7. New Zealand Guidelines Group (2012). New Zealand Primary Care Handbook 2012 (3rd Edition). Wellington: Ministry of Health.
8. World Health Organisation (2015). Guideline: Sugars intake for adults and children. Geneva.
9. Wolpert H, Atakov-Castillo A, Smith S, Steil G (2013). Dietary fat acutely increases glucose concentrations and insulin requirements in patients with type 1 diabetes: implications for carbohydrate-based bolus dose calculation and intensive diabetes management. Diabetes Care 36: 810-816.
10. Smart C, Lopez, P, Evans M et al. (2013). Both dietary protein and fat increase postprandial glucose excursions in children with type 1 diabetes, and the effect is additive. Diabetes Care 36: 3897-3902.
11. Bell K, Smart C, Steil G et al. (2015). Impact of fat, protein, and glycemic index on postprandial glucose control in type 1 diabetes: implications for intensive diabetes management in the continuous glucose monitoring era. Diabetes Care; 38: 1008-1015.
12. Ministry of Health (2014). Quality Standards for Diabetes Care Toolkit Wellington www.health.govt.nz/publication/quality-standards-diabetes-care-toolkit-2014.
13. Franz M, Boucher J, Evert A (2014). Evidence-based diabetes nutrition therapy recommendations are effective: the key is individualisation. Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy 7: 65-72.
14. American Diabetes Association (2015). Standards of medical care in diabetes 2015: summary of revisions. Diabetes Care 38: S1-S94.