I recently came across this article, ahead of print, a.k.a. ‘in press accepted manuscript’ which had free access, sweet! It outlines why varying degrees of lower carb intake, or carb ‘restriction’, is not only a great idea for managing type 2 diabetes but that the evidence is overwhelmingly supportive for this kind of dietary management.
I recently posted the link to a dietitian support group page on Facebook and it got a lot of heat. Dietitians tend to take a hostile and aggressive approach against any talk about ‘lower’ carbohydrate intakes. Perhaps it’s because it forces them to confront some longstanding beliefs; forcing to face one’s own biases or teachings can be uncomfortable, I know, it was for me.
But as the wise Yoda says:
“You must unlearn what you have learned”
This is the essence of true learning and growth. I am reminded of two pieces of advice from one of my profs in undergrad, 1) always challenge the assumptions and 2) be aware of the historical context of current paradigms. This advice applies perfectly to the current dialogue around dietary carbohydrate diet and diabetes management.
What does history have to do with it?
Both before, and to a large extent after, the discovery of insulin, reduction in dietary carbohydrate was the preferred treatment for diabetes. The rationale was that since diabetes is a disruption in carbohydrate metabolism which results in high blood sugar and because dietary carbohydrate has the greatest impact [i.e. raises] on blood sugar compared to protein and fat, then lowering the amount consumed would make intuitive sense. In this way, diabetes can be thought of as ‘carbohydrate intolerance’ and we approach other dietary intolerance in the same way: lactose avoidance for those with lactose intolerance, gluten avoidance for gluten intolerance [Celiac disease].
The authors cite two major historical variables that are most likely responsible for the move away from using lower carbohydrate diets:
1. the rise of the low-fat paradigm resulted in fat being replaced with carbohydrate ultimately increasing the average amount of carbohydrate consumed on a daily basis. The thought was that fat would have a longer term negative impact on health compared to the immediate benefit of lower blood sugar/better blood sugar control if carbs were restricted.
2. the discovery of insulin moved type 1 diabetes to been seen as a hormone deficiency disease; simply replace the missing hormone and metabolism would take care of itself; dietary [carbohydrate] consideration become secondary.
Although many see lower carbohydrate diets as controversial, the evidence supports their effectiveness with little risk and good compliance. For many, the phrase ‘lower carb’, ‘low carb’ and even ‘moderate carb’ conjures up images of steak, eggs and butter as the foundation of the diet or Atkins, and only the Atkins diet comes to mind, citing scary things like nutrient deficiencies, lack of fiber and the risk for all kinds of maladies from not eating loads of grains, grain products and fruit; none of which is necessarily true.
What’s in a name?
|Very low-carbohydrate ketogenic diet (VLCKD)|
|Carbohydrate, 20-50 g/day or less than 10% of the 2000 kcal/d diet, whether or not ketosis occurs. Derived from levels of carbohydrate required to induce ketosis in most people. Recommended early phase (“induction”) of popular diets such as Atkins Diet or Protein Power.|
|Low carbohydrate diet: less than 130 g/d or less than 26% total energy|
|The Institute of Medicine recommends a minimum of 130 g/day but this opinion based and not due to biological requirements.|
|Moderate Carbohydrate Diet: 26% – 45%|
|Upper limit of carbohydrate intake for this approach is 45% of calories coming form carbohydrate. This is the approximate carbohydrate intake before the obesity epidemic (43%).|
|High Carbohydrate Diet: Greater than 45%. Recommended target by Institute of Medicine|
|Most health organizations recommend 45-65% of total calories coming from carbohydrate.|
The 12 points of evidence for a lower carbohydrate diet for diabetes management
- Hyperglycemia is the most salient feature of diabetes. Dietary carbohydrate restriction has the greatest effects on decreasing blood glucose levels.
- During the epidemics of obesity & type 2 diabetes, caloric increases have been due almost entirely to increased carbohydrate.
- Benefits of dietary carbohydrate restriction do not require weight loss.
- Although weight loss is not required for benefit, no dietary intervention is better than carbohydrate restriction for weight loss.
- Adherence to low-carbohydrate diets in people with type 2 diabetes is at least as good as adherence to any other dietary intervention & is frequently significantly better.
- Replacement of carbohydrate with protein is generally beneficial.
- Dietary total & saturated fat do not correlate with risk of CVD [see 5 Reasons Why I’m Not Worrying About Saturated Fat].
- Plasma saturated fatty acids are controlled by dietary carbohydrate more than by dietary lipids.
- The best predictor of micro-vascular &, to a lesser extent, macro-vascular complications in patients with type 2 diabetes, is glycemic control (HbA1c).
- Dietary carbohydrate restriction is the most effective method (other than starvation) of reducing serum triglycerides & increasing high-density lipoprotein (HDL).
- Patients with type 2 Diabetes on carbohydrate-restricted diets reduce & frequently eliminate medication. People with type 1 usually require lower insulin amounts.
- Intensive glucose lowering by dietary carbohydrate restriction has no side effects comparable to the effects of intensive pharmacological treatment.
Putting it into practice
Lower carb diets can easily be implemented without much effort and don’t have to be as strict as a ketogenic diet [20-50 g carbs/day] to reap the benefits. Think of the Zone, South Beach Diet or similar that focus on non-starchy vegetables, minimal fruit, nuts & seeds, meats, fish, pulses [chickpeas, lentils, dried peas & beans], Greek yogurt, eggs, and aged cheeses [bonus is vitamin K2 – see post] and you’ll have a lower carb intake. A model of eating such as this will easily move you into the 40-45% carbohydrate intake range; if a slightly lower carbohydrate intake is desired, this can be done without much effort as well.
Forgetting the premise around a Paleo diet [i.e. are grains & pulses really that bad?], for point of illustration, you’ll see from here that meeting nutrient requirements is more than possible on a lower carbohydrate [less grains, grain products, milk, fewer fruit and added sugars] intake and any fear mongering about unbalanced diets is inflammatory.
A lower/moderate carb kind of approach can help to reduce blood pressure, boost HDL cholesterol, reduce triglycerides and ensure the production of the right type of LDL cholesterol [large fluffy, not small dense] all the while controlling the amount of carbohydrate that ultimately ends up in your blood; keeping blood sugar within a healthy range is the goal of diabetes management. This is a far cry from consuming large amounts of carbohydrate and then having to chase it with insulin in an attempt to bring it down which can result in dangerous low blood sugars, not to mention many well-established side effects of anti-diabetes medications.
Check out a great article on this topic that was in Diabetes Spectrum by dietitian Franziska Spritzler