Nutrition therapy for diabetes: A marathon, not a sprint
A brief review of the 2019 ADA consensus report on nutrition therapy for adults with diabetes or prediabetes
The subject of nutrition in diabetes is one of the hottest topics for people with diabetes, particularly those with newly diagnosed type 2 diabetes or prediabetes. Given that nutrition science is still relatively young, it’s no surprise that questions abound over the “best” diet or diets, for this population.
As Pam Dyson and Liz Morris recently discussed, seeking answers to the “best diet” question online can lead patients toward unsafe or unproven approaches for weight loss and glycemic control. Hence, there is a need to equip healthcare professionals with evidence-based consensus to put risky or unsafe diets into context and present alternatives that cater to the needs of the individual.
In the USA, the American Diabetes Association (ADA) has long been the organization that has outlined the most up-to-date, evidence-based recommendations for diabetes care providers.
A wider scope, but not wide enough?
In April 2019, the ADA writing group published an update to their nutrition therapy recommendations for adults with diabetes. The previous report was published in 2014 and did not include prediabetes. While coverage of prediabetes is a welcome and much-needed addition, the 2019 report still does not tackle nutrition in children with diabetes or women with gestational diabetes.
Similarities with guidance from Diabetes UK and Diabetes Canada
In the past, the ADA’s recommendations have steered clear of more controversial nutrition practices. However, the authors of the 2019 update were prudent enough to address them head on. Fad diets with little or no evidence of safety or efficacy have the opportunity to spread faster than ever via the internet, so it’s unsurprising that more people with diabetes are adopting or posing questions about popular diets that lack sufficient evidence of benefit in people with diabetes. To counter patient reliance on misinformation it is crucial that healthcare providers are equipped with the evidence, instead of outright criticism or dismissal of what patients have seen online or heard from their peers.
The ADA’s 24-page document includes 345 references and 40 consensus recommendations that are the “informed, expert opinions of the authors after consensus was reached through presentation and discussion of the evidence”. While this may seem quite lengthy, Diabetes UK’s evidence-based nutrition guidelines for the prevention and management of diabetes (discussed by guideline author Pam Dyson in an earlier editorial), is merely a summary of the full 114-page report found online, and includes 51 recommendations. Diabetes Canada also published their nutrition guidelines in 2018, which included 14 recommendations and key messages for people with diabetes.
The fact remains, that while many do not feel that nutrition therapy is “rocket science,” there are a multitude of considerations that do make this discussion far more complex than people are led to believe. I often see confusion and frustration around nutrition therapy from people with diabetes, as well as the healthcare professionals charged with helping patients to manage their disease – I believe that a lack of consistent messaging in the past has contributed to this problem. However, I also believe that the latest documents from the ADA, Diabetes UK, and Diabetes Canada go a long way to aid in clarifying and solidifying consistent communication on nutrition for people with diabetes.
Low-carb and very low-carb eating patterns may have a place for some with diabetes
While many of the recommendations are similar between the organizations, new to the ADA recommendations is the need for a more robust discussion surrounding eating patterns. Four consensus recommendations have been included in the eating patterns section, highlighting and recommending the “usual suspects” for healthy eating. These include:
- Mediterranean diets,
- vegetarian or Vegan diets, and
- Dietary Approaches to Stop Hypertension (DASH) diets.
But this update also discusses the use of low-carb (defined as 26–45% of total calories), very low-carb (20–50 g of non-fiber carbohydrate per day, <26% of total calories) and Paleolithic-style “Paleo” diets. According to the consensus report, research has revealed that low-carb and very low-carb diets lead to glycated hemoglobin (HbA1c) reduction, weight loss, lowered blood pressure, increased high-density lipoprotein cholesterol and lowered triglycerides, while Paleo diets have had mixed results and have provided inconclusive evidence.
Reducing carbohydrate intake has always, to some extent, been the cornerstone of nutrition therapy in diabetes; two new eating pattern recommendations in this vein are highlighted in the ADA’s document:
- Reducing overall carbohydrate intake for individuals with diabetes has demonstrated the most evidence for improving glycemia and may be applied in a variety of eating patterns that meet individual needs and preferences.
- For select adults with type 2 diabetes not meeting glycemic targets or where reducing antiglycemic medications is a priority, reducing overall carbohydrate intake with low- or very low-carbohydrate eating plans is a viable approach.
Source: Evert et al. Nutrition therapy for adults with diabetes or prediabetes: A consensus report. Diabetes Care 2019; 42: 731–754.
Given that it is common for people with diabetes to have questions about and requests to follow these dietary approaches, having specific discussion points to address queries will lead to a less adversarial conversation and aid people to make informed choices for change.
The carbohydrate–calorie conversion clarified
Of particular interest, is a quick reference table that quantifies the conversion of percent calories from carbohydrate in grams per day in varying calorie amounts. For a 2000-calorie per day meal plan, 20% of total calories from carbohydrate is 100 g; for a 1500-calorie per day meal plan, 30% of total calories from carbohydrate is 113 g. This is an excellent teaching tool to really explain and clarify actual carbohydrate intake for various calorie needs, instead of providing patients with blanket statements to encourage eating “lower carb”.
Nutrition education should be delivered by a registered dietitian
One of the key messages that continues to emerge from the updated ADA nutrition recommendations (also included in the 2014 position statement) is the call to action for healthcare providers to refer their patients with diabetes to a registered dietitian nutritionist (US terminology) for medical nutrition therapy, in order to make the most positive impact on outcomes. Diabetes UK and Diabetes Canada also recommend interaction with a registered dietitian.
Nutrition therapy is an ongoing process
The current ADA recommendations for implementing medical nutrition therapy include three to six education visits during the first 6 months following a type 2 diabetes diagnosis, and at least one annual follow-up visit. During this period, I believe that as healthcare professionals we should:
- Remember that nutrition therapy is a very personal, individualized process – not all recommendations will resonate with every person with diabetes;
- recognize that the behavior change that nutrition therapy encourages is a process that rarely happens overnight;
- be cognizant that the average adult can handle only one or two recommendations at a time;
- accept that, while receiving one nutrition education session from a registered dietitian may be a helpful first step, ongoing follow-up is crucial to fine-tune goals and improve the chances of success for positive nutrition behaviors for the long term.
Nutrition changes take time
As I say to my patients, meal planning changes are “a marathon, not a sprint”. It takes time to observe how any changes implemented have affected each individual; it also takes time to alter changes if they have not elicited the appropriate response. Being realistic with expectations is fundamental to making long-term nutrition changes that people with diabetes will actually continue for their lifetimes.
Recommendations, like those delivered by the ADA, can serve as the blueprints for conversations with patients that ultimately lead them towards individualized diet and nutrition and, with time, better diabetes outcomes.