The CSIRO, in collaboration with several universities and research institutions, undertook a large and complex diet and lifestyle intervention study to better understand methods for managing type 2 diabetes.
Over 1 year, 115 participants with type 2 diabetes were split into two groups for eating:
- a low-carbohydrate (14% carbohydrates at 50g per day; 28% protein; 58% fat (<10% saturated)) group
- high-unrefined carbohydrate (53% carbohydrates; 17% protein; 30% fat (<10% saturated)) group.
The dietary protocols were energy matched, and they did this alongside an exercise program.1
Those on the low-carb regime experienced a whopping 40% decrease in medication requirements, 2 times that of the high-carb low-fat diet – who consumed 205g per day. And the low-carb diet was 3x more effective for reducing spikes in blood glucose throughout a day.
“Health professionals have been divided over the best dietary approach for managing type 2 diabetes, and the ongoing uncertainty is a hotly debated topic amongst clinicians and researchers,” said Associate Professor Grant Brinkworth and study author.
“This research shows that traditional dietary approaches for managing type 2 diabetes could be outdated, we really need to review the current dietary guidelines if we are serious about using the latest scientific evidence to reduce the impact of the disease.”
More recently, a U.K. based systematic review of intervention studies involving participants with type 2 diabetes and effect of restricted carbohydrate intake on metabolic outcomes.2
The researchers found glycated haemoglobin levels fell when reducing carbohydrate intake to 120g per day, with the greatest reduction seen with limits of 30g per day.
What is glycated haemoglobin, you may ask? It is formed when the protein in red blood cells called haemoglobin is bound with glucose. It is used to determine blood glucose levels over a longer period.
Weight loss was also seen, and excitingly, a possible positive side effect of improvements in mood. This may be due to less extreme fluctuations in blood glucose, which can lead to low blood sugar levels between meals and subsequent fatigue, low mood, and propensity to eat more refined starch and sugar for a quick energy and mood boost.
Weight loss was also seen, and excitingly, there is the possible side effect of improvements in mood. This may be due to less extreme fluctuations in blood glucose, which can lead to low blood sugar levels between meals and subsequent fatigue, low mood, and propensity to eat more refined starch and sugar for a quick energy and mood boost.
“More long-term studies are required to ensure that the results can be confidently translated into clinical practice, however, the science at this point in time is compelling and should not be ignored,” said lead author Michelle McKenzie.
And the compelling body of science continues to grow.
Professor Sarah Hallberg of Indiana University and her team found 89% of the 238 participants following their low-carbohydrate high-fat diet were able to reduce or cease their reliance on insulin medication. In as little as 10 weeks. Wow!3
The participant’s dietary protocol involved <30g of carbohydrates, 1.5g/kg of body weight of protein, incorporating healthy fats, and encouragement to consume 3-5 serves of non-starchy vegetables, per day.
A possible factor leading to such great results could be the individualised prescriptions of diet for each participant, and there is an emphasis on eating real food, as with many intervention trials. This too will benefit health.
All sounding positive! So, what exactly is the definition of low-carb?
Low-carb in a nutshell
Low-carb, according to Diabetes UK is anything under 45% total energy intake from carbohydrate rich foods. It has also been broken down as such:
- Moderate carbohydrate: 130 to 225g of carbohydrates
- Low-carbohydrate: under 130g of carbohydrates
- Very-low-carbohydrate: under 30g of carbohydrates4
A healthy low-carb diet focuses on a strong intake of vegetables and includes healthy, natural sources of fat and a moderate amount of protein. Whole grains, starches, fruits and sugars can be included in small amounts, and processed food is pretty much out of the picture.5
A very-low-carbohydrate (a.k.a. ketogenic) treatment – less than 30g of carbohydrates – is the extreme end of the low-carb scale, and may exclude all grains, starches, fruits and sugars. While it has been trialled for the treatment of specific health conditions such as type 2 diabetes (like the Indiana University intervention above) and epilepsy, for the majority of us we need not be so extreme.
If you are insulin resistant or type 2 diabetic and considering a very-low-carbohydrate dietary protocol as treatment, chat with your qualified healthcare practitioner who is knowledgeable on the topic and can guide you in eating this way safely.
Just eat real food
What everyone can focus more of their food energy on is real, whole food and limiting intake of refined flours, refined grains and added sugars. These are heavily processed ingredients, food, or drink that serve little nutritional value, unlike their whole food counterparts such as wholemeal spelt flour, whole oats, or a whole fruit that can offer fibre and other nutrients with minimum impact to the body.
And remember, low-carb is not ‘no-carb’. Just like choosing healthy fats, choose whole food sources of carbohydrate-rich foods. Most can tolerate a little, and ensure if you have some it is of super-good quality.
By Angela Johnson (BHSc Nut. Med.)
- Tay, J, Luscombe-Marsh, ND, Thompson, CH, Noakes, M, Buckley, JD, Wittert, GA, Yancy Jr., WS, & Brinkworth, GD 2015, ‘Comparison of low- and high-carbohydrate diets for type 2 diabetes management: a randomized trial’, American Journal of Clinical Nutrition, vol. 102, no. 4, pp. 780-790.
- McKenzie, M & Illingworth, S 2016, ‘Should a Low-carbohydrate Diet be Recommended for Diabetes Management?’, Proceedings of the Nutrition Society, vol. 76, Issue OCE1.
- McKenzie AL, Hallberg SJ, Creighton BC, Volk BM, Link TM, Abner MK, Glon RM, McCarter JP, Volek JS, & Phinney SD 2017, ‘A Novel Intervention Including Individualized Nutritional Recommendations Reduces Hemoglobin A1c Level, Medication Use, and Weight in Type 2 Diabetes’, JMIR Diabetes, vol. 2, no. 1.
- Diabetes UK 2017, Low Carb, viewed 13 March 2017, <http://www.diabetes.co.uk/diet/low-carb-diabetes-diet.html>
- Diabetes UK 2017, How to Follow a Healthy Low Carb Diet, viewed 13 March 2017, <http://www.diabetes.co.uk/diet/how-to-follow-a-healthy-low-carb-diet.html>