What about going Keto?

Joint post with Ellen Rushmer

The ketogenic diet is a extremely low carbohydrate diet, very high fat diet. The theory is when you heavily restrict carbohydrate intake, your metabolism switches from burning glucose (carbs) to burning fat stores (ketone bodies).

Our bodies have a preferred fuel they like to run off like our cars. For the body it prefers to have glucose. When there is no glucose around it will use glycogen stores (glucose stored in the muscles and liver) and when this runs out it will use fat. This may sound good but read on….

Where has it come from?

Developed in the 1920’s as a treatment for children with epilepsy, who did not respond to drugs. Even now doctors do not understand exactly why this diet works for reducing seizures, but we do know that it works. This is a dietary treatment used clinically under full medical supervision. The question is how and why has it become a mainstream weight loss diet?

Is it a good idea?

  • To eat low carb you have to avoid wholegrains and high fibre foods. The government, the NHS and public health guidelines recommend everyone should be aiming for at least 30g of fibre each day and most of us are onyl achieving 19g/d. The science shows us that eating wholegrains offers a whole host of benefits on our gut health, our heart health and our weight management too. So we don’t want to be reducing our fibre but increasing it! Not getting enough fibre can also mean constipation is a common side effect because the rate of digestion is slowed down. 
  • Your brain heavily relies on glucose as a fuel, so this diet can have a profound effect upon cognitive functions (i.e. brain fog).
  • Carbohydrate attracts a lot of water when broken down and is known as a ‘bulky molecule’, so when people reduce carbohydrate intake, the initial weight loss they experience is just water weight, not actual fat loss. 
  • The diet advocates increasing saturated fat intake. Saturated fat has long been associated with CHD, high cholesterol and hypertension and guidelines recommend we should be limiting our saturated fat intake to no more than 11% of your overall diet. This diet is advocating something drastically different from the evidence based healthy eating guidelines- something to be wary of. 
  • It means eating no more than 50g carb/day (equivalent to one banana). That’s hard to do, very hard.
  • You may feel lighter- for 2 reasons: your restricting both calories and food groups. It is really hard to eat a very high fat diet long term, because you are likely to feel quite sick and full from the high proportion of high fat foods. Long term it is hard to stick to a diet like this (as those using it clinically as a treatment for epilepsy) inevitably leading to ‘falling off the bandwagon’, and blaming yourself for a lack of ‘self-control’ fuelling the desire to diet once again.

Is there any research/ evidence for it?

  • There is NO research whatsoever for using the keto diet as a public health strategy. There is no data suggesting this way of eating is beneficial for humans, or for the planet either. The keto diet is very high in animal products including red meat which we know is not sustainable and there is evidence showing we need to be reducing animal consumption and animal products whilst increasing plant-based foods 
  • Interestingly, when high fat-low carb diets are compared with low fat-high carb diets: the weight loss seen in 2 groups of individuals is very similar, and perhaps more importantly the weight does seem to creep back (regardless of the diet) because diets are very hard to stick to for a myriad of reasons.

Take-home message:

The Keto diet is not recommended (unless you have epilepsy and and are doing the diet under full supervision of a registered dietitian).

Fibre and carbohydrates are nutrients our body needs. Going on a restrictive diet is not good for your long term physical or mental health. Instead find ways to make long term changes to your eating and movement that you can stick to, things that make you feel good!

Thanks to Ellen Rushmer for her help with this post

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