Should you go keto?

DL dietitian and diabetes educator Dr Kate Marsh discusses the current evidence on keto diets

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Ketogenic diets aren’t new and have been used for many years for the treatment of epilepsy in children who don’t respond to drug treatment. However, they have recently made a resurgence and are being promoted for everything from weight loss to reversing diabetes and preventing Alzheimer’s disease.

But is going keto really the answer to managing your diabetes and weight? Let’s discuss.

WHAT EXACTLY IS A KETOGENIC DIET?

A ketogenic (keto) diet is an eating plan that is very low in carbohydrate (about 20-50g per day) and high in fat, with an adequate (but not high) intake of protein.

The low carbohydrate content of the diet means the body doesn’t have much glucose to use as a fuel, so instead uses fat as its main energy source. The breakdown of fat by the liver, a process called ketosis, results in the production

of ketones, a type of acid. The ketones are sent to your bloodstream where, as long as you have enough insulin around, they can be used as a fuel by muscles and other tissues.

HOW CAN A KETO DIET HELP?

Cutting carbs to 20-50g per day means eliminating processed carbs and added sugars, which is something that everyone can benefit from.

Several studies have shown significant weight loss, improvements in blood glucose and insulin levels, reductions in diabetes medication use, a reduction in triglycerides (blood fats) and an increase in ‘good’ HDL cholesterol levels in those following a keto diet.

There is also some evidence the production of ketones reduces appetite, which may help with weight loss.

WHAT ARE THE DOWNSIDES TO KETO?

While a keto diet might seem like the perfect solution to managing diabetes (cut carbs and your BGLs will be lower), unfortunately it’s not that simple.

In fact, studies have shown that while low-carb, high-fat diets lead to a reduction in blood glucose and insulin levels in the short term, they can actually worsen insulin resistance and glucose tolerance in some people. This is more likely to occur if you follow the diet without losing weight.

There is also evidence high-fat diets lead to unfavourable changes in gut bacteria, which may have negative effects on our health. And Australian researchers have discovered a low-carb diet can affect the growth of children with type 1.

Keto diets also restrict many of the foods we know are beneficial for good health, including wholegrains, legumes, fruits and some vegetables. Research has shown eating more of these foods is associated with a reduced risk of many chronic diseases, such as type 2, cardiovascular disease and some types of cancer.

The long-term effects of following ➤

a keto diet are unknown, but this type of eating plan is very different to the diets of longlived healthy populations, which all consume a mostly plant-based diet.

IS A KETO DIET REALLY BETTER THAN OTHER TYPES OF DIET?

Any diet that reduces your kilojoule intake will help you to lose weight. And any diet that helps you to lose weight is very likely to lower BGLs, by helping your insulin to work better.

Keto diets are no exception and a number of studies have shown this. But what advocates of a keto diet fail to point out is that other diets, which may be easier to follow in the long term, such as a Mediterraneanstyle diet, have shown similar benefits. In fact, controlled feeding studies, where they have kept the kilojoule intake of both diets the same, have found no greater fat loss on a keto diet compared with a higher-carbohydrate, low-fat diet. And randomised controlled trials of a low-fat vegan diet have shown similar improvements in BGLs and reductions in medication use, with a much lower fat and higher carbohydrate intake.

A HEALTHIER WAY TO GO KETO

If you decide keto is right for you, there are a few things you can do to reduce the potential downsides and optimise the health benefits of a low-carb, high-fat diet.

• Get most of your fat from avocados, nuts, seeds, olive oil and oily fish, rather than fatty meats, palm oil and coconut oil.

• Up your intake of nonstarchy vegetables to increase your intake of fibre and important vitamins, minerals and antioxidants.

• Avoid processed meats, limit red meat and eat more fish and plant proteins such as tofu, tempeh, nuts and seeds.

IN SUMMARY

Keto diets are one way to lose weight and improve blood glucose levels, at least in the short term, but they are not the only way, and similar results can be obtained with a lowerfat, higher-carb diet, as long as you choose higher-fibre, lower Glycemic Index (GI) carbs such as fruits, vegetables, legumes and minimally processed wholegrains.

The key to long-term weight loss and diabetes management is finding a diet you enjoy and can stick to.

And the best evidence we have for a diet consistent with long-term health and disease prevention is a mostly plant-based diet that includes plenty of healthy, carbohydratecontaining foods.