Diabetes Canada 2018 Clinical Practice Guidelines – option of a low carb diet


Diabetes Canada has released their long-awaited 2018 Clinical Practice Guidelines [1] which affirms that nutrition therapy is an integral part of people’s self-management of their Diabetes, as well as part of the treatment for the disease.  One of the main goals of nutrition therapy is to maintain or improve the quality of life and nutritional and physical health of those with the disease, while preventing the need to treat both sudden (acute) and long term complications. Effective nutrition therapy can improve blood sugar control, including reducing three-month average blood glucose (i.e. HbA1C, glycated hemoglobin) by 1.0% to 2.0%.

Diabetes Canada 2018 Clinical Practice Guidelines

The new Guidelines mention that since Canada has wide ethnic and cultural diversity, with each group having their distinct foods, preparation methods, and dietary patterns and lifestyles. Effective nutritional therapy needs to take these cultural variations into account and needs to be individualized;  specific to the individual, their age, the duration they’ve had type 2 diabetes, their goals, personal values and preferences, along with their individual need, lifestyle and economic situation. They recognize that nutrition therapy for those with Diabetes is not “one-size-fits-all”.

“Nutrition therapy should be individualized, regularly evaluated, reinforced in an intensive manner and should incorporate self-management education. A registered dietitian (RD) should be involved in the delivery of care wherever possible.”

The Nutrition Therapy Guidelines recommend that those with Diabetes follow the recommendations of Eating Well with Canada’s Food Guide;

“The starting point of nutrition therapy is to follow the healthy
diet recommended for the general population based on Eating Well With Canada’s Food Guide.”

They recommend that those with Diabetes continue to eat 45% to 65% of their daily calories as carbohydrate, 10% to 35% of their daily calories as protein and only 20% to 35% of their daily calories as fat, yet at the same time say that “the ideal macronutrient distribution for the management of diabetes can be individualized”;

“The ideal macronutrient distribution for the management of diabetes can be individualized. Based on evidence for chronic disease prevention and adequacy of essential nutrients, the DRIs (Dietary Reference Intakes) recommend acceptable macronutrient distribution ranges (AMDRs) for macronutrients as a percentage of total energy. These include 45% to 65% energy for CHO, 10% to 35% energy for protein and 20% to 35% energy for fat.”

They recommend that those with Diabetes continue to follow the same macronutrient distribution (percent of carbs, protein and fat) as the general population because it

“may help a person attain and maintain a healthy body weight while ensuring an adequate intake of carbohydrate (CHO), fibre, fat, protein, vitamins and minerals.”

What is encouraging is that they also have said that there is evidence to support a number of other macronutrient-, food- and dietary pattern-based approaches and advise against any rigid adherence to any one approach;

“There is evidence to support a number of other macronutrient-, food- and dietary pattern-based approaches. As evidence is limited for the rigid adherence to any single dietary approach, nutrition therapy and meal planning should be individualized.”

These Guidelines leave it open to individuals to choose other dietary approaches and outline a number of those approaches in the body of the text and in a summary table (Table 1). Figure 1 and Figures 2 and Table 1 in the Clinical Practice Guidelines (below) present an algorithm that summarizes the approach to nutrition therapy for diabetes which includes;

“allowing for the individualization of therapy in an evidence-based framework”.

Figure 1 – Clinical Assessment – Diabetes Canada 2018 Clinical Practice Guidelines

Figure 2 – Stage Targeted Nutrition Flowchart – Diabetes Canada 2018 Clinical Practice Guidelines

Table 1:

Table 1: Properties of Dietary Intervention – Diabetes Canada 2018 Clinical Practice Guidelines

The new Diabetes Canada guidelines recognize that the ideal macronutrient distribution (the ratio of carbs, protein and fat) may vary and depend on, amongst other things, the individual’s values and preferences;

“The ideal macronutrient distribution for the management of diabetes may vary, depending on the quality of the various macronutrients, the goals of the dietary treatment regimen and the individual’s values and preferences.”

That is, they recognize that a person’s individual preference for the amount and type of protein (animal-based, plant-based, both), fat (from animal or plant based sources), as well as the amount and type of carbohydrate in their diet factors into their personal decision for how they choose to manage their diabetes.

The Clinical Practice Guidelines for Nutrition Therapy mentions that based on the 3 systematic and meta-analysis of controlled trials of carbohydrate restricted diets that they looked at (mean carbohydrate intake from 4% to 45% of total daily energy) that consistent improvements in HbA1C, lipids and blood pressure weren’t shown.

“As for weight loss, low-carbohydrate diets for people with type 2 diabetes have not shown significant advantages for weight loss over the short term. There also do not appear to be any longer-term advantages.”

So while they do not believe based on the few studies that they examined that there is any advantage to someone following a low carbohydrate diet, there are no clear disadvantages. It comes down to individual preference.

The Guidelines also highlight that there may be a benefit of substituting monounsaturated fat (MUFAs) such as is found in olive oil for carbohydrate (something I regularly do when I design Meal Plans) and that systematic review and meta-analysis of randomized controlled trials found that monounsaturated fat substituted calorie for calorie for carbohydrate did not reduce HbA1C, but did improve fasting blood glucose, body weight, systolic BP, triglycerides and HDL (so-called “good cholesterol”) in people with type 2 diabetes over an average follow up of 19 weeks.

Another finding they reported is that replacement of refined high glycemic index carbohydrates with monounsaturated fat (up to 14.5% total energy) or nuts (up to 5% total energy) has been shown to improve HbA1C and lipids in people with type 2 diabetes over a 3 month period.

Together, these findings provide support to those who prefer to replace high glycemic carbs in their diet (such as white bread, pasta and rice) with monounsaturated fat sources such as olives, avocado as well as some nuts.

The new Clinical Practice Guidelines outline several popular weight-loss diets highlighting that there are a “range of macronutrient profiles are available to people with diabetes”;

“Numerous popular weight-loss diets providing a range of macronutrient profiles are available to people with diabetes. Several of these diets, including the Atkins™, Zone™, Ornish™, Weight Watchers™ and Protein Power Lifeplan™ diets, have been subjected to investigation in longer-term, randomized controlled trials in participants with overweight or obesity that included some people with diabetes, although no available trials have been conducted exclusively in people with diabetes.

They say that a systematic review and meta-analysis of four trials of the Atkins™ diet and 1 trial of the Protein Power Lifeplan™ diet showed that these diets were no more effective than conventional energy-restricted, low-fat diets in inducing weight loss, or with improvements in triglycerides and HDL for up to one year and have been reported to increase total cholesterol and LDL. As mentioned in an earlier article, without differentiating between particle size of LDL (small, dense versus large, fluffy), LDL and total cholesterol going up has not real meaning.

The Guidelines also mentioned that “The Dietary Intervention Randomized Controlled Trial (DIRECT) showed that the Atkins™ diet produced weight loss and improvements in the lipid profile compared with a calorie-restricted, low-fat conventional diet; however, its effects were not different from that of a calorie-restricted Mediterranean-style diet at two years.”

They add that “another trial comparing the Atkins™, Ornish™, Weight Watchers™ and Zone™ diets showed similar weight loss and improvements in the LDL:HDL ratio without effects on fasting blood sugar at one year in participants with overweight or obesity, of whom 28% had diabetes.

So again, it comes down to a matter of choice as to whether someone would prefer to do a calorie-restricted weight loss diet or a well-designed low carb one.

At the end of the paper, the authors make their final recommendations, some of which include that;

“People with diabetes should receive nutrition counselling by a registered dietitian to lower A1C levels and to reduce hospitalization rates”.

“Individuals with diabetes should be encouraged to follow Eating Well with Canada’s Food Guide in order to meet their nutritional needs.”

“In people with overweight or obesity with diabetes, a nutritionally balanced, calorie-reduced diet should be followed to achieve and maintain a lower, healthier body weight”.

“An intensive healthy behaviour intervention program, combining dietary modification and increased physical activity, may be used to achieve weight loss, improve glycemic control and reduce CV risk.”

“In adults with diabetes, the macronutrient distribution as a percentage of total energy can range from 45% to 60% carbohydrate, 15% to 20% protein and 20% to 35% fat to allow for individualization of nutrition therapy based on preferences and treatment goals.”

“People with type 2 diabetes should maintain regularity in timing and spacing of meals to optimize glycemic control.”

“To reduce the risk of cardiovascular disease, adults with diabetes should avoid trans fatty acids and consume less than 9% of total daily energy from saturated fatty acids, replacing these fatty acids with polyunsaturated fatty acids, particularly mixed n-3 / n-6 sources, monounsaturated fatty acids from plant sources, whole grains or low glycemic index carbohydrates”

“Adults with diabetes should select carbohydrate food sources with a low-GI to help optimize glycemic control to improve LDL and to decrease cardiovacular risk.”

“The following dietary patterns may be considered in people with type 2 diabetes, incorporating patient preferences, including:

(a) Mediterranean-style dietary pattern to reduce major cardiovascular events and improve glycemic control.

(b) Vegan or vegetarian dietary pattern to improve glycemic control and reduce myocardial infarction risk.

(c) DASH dietary pattern to improve glycemic control and reduce major cardiovascular events.

(d) Dietary patterns emphasizing dietary pulses (e.g. beans, peas, chickpeas, lentils) to improve glycemic control, systolic BP and body weight.

(e) Dietary patterns emphasizing fruit and vegetables to improve glycemic control and reduce CV mortality.

(f) Dietary patterns emphasizing nuts to improve glycemic control and LDL cholesterol.

Funding sources for the three authors of the Nutrition Therapy guidelines were as follows; Dr. John L. Sievenpiper, MD, PhD; Canadian Institutes of Health Research (CIHR), Calorie Control Council, INC International Nut and Dried Fruit Council Foundation, The Tate and Lyle Nutritional Research Fund at the University of Toronto, The Glycemic Control and Cardiovascular Disease in Type 2 Diabetes Fund at the University of Toronto (a fund established by the Alberta Pulse Growers), PSI Graham Farquharson Knowledge Translation Fellowship, Diabetes Canada Clinician Scientist Award, Banting & Best Diabetes Centre Sun Life Financial New Investigator Award, and CIHR INMD/CNS New Investigator Partnership Prize; grants and non-financial support from American Society for Nutrition (ASN), and Diabetes Canada; personal fees from mdBriefCase, Dairy Farmers of Canada, Canadian Society for Endocrinology and Metabolism (CSEM), GI Foundation, Pulse Canada, and Perkins Coie LLP; personal fees and non-financial support from Alberta Milk, PepsiCo, FoodMinds LLC, Memac Ogilvy & Mather LLC, Sprim Brasil, European Fruit Juice Association, The Ginger Network LLC, International Sweeteners Association, Nestlé Nutrition Institute, Mott’s LLP, Canadian Nutrition Society (CNS), Winston & Strawn LLP, Tate & Lyle, White Wave Foods, and Rippe Lifestyle, outside the submitted work; membership in the International Carbohydrate Quality Consortium (ICQC) and on the Clinical Practice Guidelines Expert Committees of Diabetes Canada, European Association for the study of Diabetes (EASD), Canadian S74 J.L. Sievenpiper et al. / Can J Diabetes 42 (2018) S64—S79 Cardiovascular Society (CCS), and Canadian Obesity Network; appointments as an Executive Board Member of the Diabetes and Nutrition Study Group (DNSG) of the EASD, Director of the Toronto 3D Knowledge Synthesis and Clinical Trials foundation; unpaid scientific advisor for the Food, Nutrition, and Safety Program (FNSP) and the Technical Committee on Carbohydrates of the International Life Science Institute (ILSI) North America; and spousal relationship with an employee of Unilever Canada. Dr. Chan reports grants from Danone Institute, Canadian Foundation for Dietetic Research, Alberta Livestock and Meat Agency, Dairy Farmers of Canada, Alberta Pulse Growers, and Western Canada Grain Growers. Dr. Catherine B Chan has a patent No. 14/833,355 pending to the United States. Dr. Catherine Freeze, MEd, RD reports personal fees from Dietitians of Canada and Government of Prince Edward Island.

Some Final Thoughts…

Much of the same wording  regarding supporting individual preference was previously embodied in the 2013 Clinical Practice Guidelines of the Canadian Diabetes Association. While not “recommended”, there was previously the same option for individuals to choose to follow a low carb lifestyle, based on personal preference.

As a Dietitian, I keep reading and reviewing the literature in order to provide the most current, evidence-based low carbohydrate diet to support those that choose to follow a low carb lifestyle — or who’s doctors recommend that they do, and in this way allow for the individualization of nutrition therapy in an evidence-based framework.

Do you have questions as to how I can help support your preference to follow a low carb lifestyle? Please send me a note using the “Contact Me” form on this web page and I’ll reply as soon as possible.

To our good health,

Joy

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References

  1. Sievenpiper JL, Chan CB, Dwortatzek PD, Freeze C et al, Nutrition Therapy – 2018 Clinical Practice Guidelines, Canadian Journal of Diabetes 42 (2018) S64—S79 http://guidelines.diabetes.ca/docs/CPG-2018-full-EN.pdf

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