It would be near impossible to have not stumbled across #keto if you’ve spent any time on social media. In addition to being associated with photos of body transformations and platters of meat and cheese, in recent times it has also started to be considered as an approach for managing diabetes.
What is keto?
A ketogenic diet is a very low carbohydrate diet where less than 10% of your total energy needs come from carbohydrate–based foods. This equates to between 20-50g of carbohydrates per day. To put it into perspective 2 slices of bread will get you there.
There is emerging evidence showing positive results in blood glucose management using a ketogenic diet – after all the amount of carbohydrates in our diet has a direct influence on blood glucose levels. But nutrition is never that simple, and here are 5 reasons why a ketogenic diet isn’t necessarily the best long-term solution to managing diabetes.
1. Increased risk of nutrient deficiencies
A ketogenic diet involves cutting out whole entire food groups in a bid to avoid carbohydrates, so it really shouldn’t come as a surprise there’s likely to be a few essential vitamins and minerals that you won’t be getting. Our main carbohydrate containing foods are:
- grain–based foods (breads, cereals, pasta, rice etc)
- fruit
- starchy vegetables (also in smaller quantities in other vegetables)
- legumes
- dairy products (milk and yoghurt – most cheeses are allowed in a ketogenic diet)
Avoid all of these and you are at risk of deficiencies in B group vitamins, calcium, selenium and even vitamin C – unless of course you’ve got your low carb vegetable A–game on!
2. Constipation
It’s not surprising that #ketoconstipation doesn’t trend anywhere near as well on social media as some of the other keto hashtag derivatives because let’s face it, it’s not as sexy and glamourous. But the truth of the matter is that constipation is a very common experience for those following a very low carb diet. The best sources of fibre in our diet all come from carb sources – grain-based foods, legumes, fruit and vegetables. Cut these out and your gut health is going to suffer.
3. Increase in cardiovascular disease risk
When you look at the macronutrient breakdown of a ketogenic diet, fat intake accounts for anywhere between 64-90% of total energy intakes (compared to around 35% of a “normal” diet). This much larger intake of fats can lead to abnormal blood cholesterol levels. The main reason for this is an increase in the use of saturated fats in the diet (coconut oil is a big one here), especially in those that start keto without seeking the advice of a dietitian.
4. Potential increase in impaired glucose tolerance and increased insulin resistance
There is emerging evidence that a low carbohydrate diet can actually lead to a cascade of metabolic changes that results in further impairment to glucose tolerance and, in some individuals, an increase in insulin resistance (1). Now this isn’t an issue while you continue to follow a keto or low carbohydrate diet but should you change your diet at any time in the future and return to a more moderate carbohydrate diet then you are going to find it very difficult to keep your BGLs under control. Which needs very careful consideration given the final point …
5. Issues with compliance
While there are certainly some people who might love a keto diet, for most of us it means having to go without many foods that we really enjoy eating. If you’ve always had a bit of a soft spot for grains, fruit or dairy then you’re likely to really struggle with a keto diet. Many people who follow keto allow themselves “cheat” days where they will eat an increased amount of carbohydrate-based foods. For many, these cheat days can rapidly spiral out of control and end up seeing a very large amount of carbohydrates eaten over the course of the day. Add onto this the potential increase in impaired glucose tolerance caused by following a keto diet and you’ve got some very poorly managed blood glucose levels.
If not keto, then what?
Believe it or not, research shows us that we can achieve great results in blood glucose management through a variety of different dietary approaches – there is never a “one size fits all” approach. Low carbohydrate and moderate carbohydrate diets have both been shown to improve HbA1C to the same degree in the long-term (2). The Mediterranean Diet, Vegetarian/Vegan and low carbohydrate diets (as opposed to the very low carb keto) are all examples of diets that have shown positive health outcomes when used in the management of diabetes (3). In fact, while the amount of carbohydrates and their distribution within the diet are all important, successful long–term weight loss is the factor that can lead to remission in type 2 diabetes (4). And the key to successful long-term weight loss is finding the diet that works well for your situation and lifestyle.
References:
- Hall and Chung. 2018. Low-carbohydrate diets for the treatment of obesity and type 2 diabetes. Clin Nutr Metab Care. 21:308-312
- Tay J et al. 2017. Comparison of low- and high- carbohydrate diets for type 2 diabetes management: a randomised trail. Diabetes Obes metab. 20:858-871.
- Evert et al. 2019. Nutrition therapy for adults with diabetes or pre-diabetes. American Diabetes Association. Diabetes Care 42:731-754.
- Lean et al. 2019. Durability of a primary care-led weight-management intervention for remission of type 2 diabetes: 2-year results of the DiRECT open-label, cluster-randomised trial. Lancet Diabetes and Endocrinology. Vol 7(5):344-355.
