Very low carb diets found to be good for the brain

I am a fan of low-carbohydrate eating, and my position is based on the science (showing it to be usually effective for weight loss and improvements in disease markers) and my experience with it in practice. However, not everyone shares my enthusiasm for this way of eating. Many people like to paint carbohydrate restriction as somehow dangerous. In quite-extreme carbohydrate restriction the body will generally turn to ketones (created from the metabolism of fat and/or protein) as a fuel source. This results is a state known as ‘ketosis’. I don’t generally recommend extreme carb restriction, but I don’t fear ketosis either. I see it as a natural response of the body to carbohydrate restriction.

All too often, I think ketosis is confused with ‘ketoacidosis’, which is a whole other story. Ketoacididosis occurs when there are severe metabolic disturbances such as when blood sugar levels run out of control in type 1 diabetics. It’s a serious situation, and potentially life-threatening but, as I say, is not the same as ‘ketosis’.

Ketones provide fuel for the body and brain, but some have questioned how well they do this compared to other fuel sources (such as glucose). I was therefore interested to read about a recent study in which a very low carbohydrate ‘ketogenic’ diet was tested in individuals with ‘mild cognitive impairment’ (reduced brain function associated with ageing but not severe enough to be classified as dementia) [1]. Half of the group in this study were randomised to eat the ketogenic diet, the other half ate a diet rich in carbohydrate. The study lasted 6 weeks.

The researchers found that those eating the ketogenic diet, compared to the other group, saw significant improvement in their ‘verbal memory’ (memory of words and other abstractions involving language). Also, generally speaking, the higher their ketone levels, the better their verbal memory tended to be. The suggestion here is that ketones provide ready fuel for the brain, and may enhance ‘cognitive function’.

Aside from memory improvement, those in the ketogenic diet also saw significant benefits in terms of weight loss and waist circumference reduction, as well as reductions in fasting blood glucose and insulin levels. Taken as a whole, these results suggest that carbohydrate restriction sufficient to induce ketosis offers, in the short term at least, significant advantages for both body and brain.


1. Krikorian R, et al. Dietary ketosis enhances memory in mild cognitive impairment. Neurobiol Aging 2 December 2010 [epub ahead of print]

15 Responses to Very low carb diets found to be good for the brain

  1. Nigeepoo 8 December 2010 at 5:47 pm #

    I totally agree that two fuels are better than one. Sadly, once people are institutionalised due to mental impairment, they’re effectively doomed as:-

    a) They get virtually zero sun exposure (and when they are occasionally taken outside on a sunny day, they’re covered from head to toe in clothes to avoid them feeling cold). I’d hazard a guess that 100% of nursing home residents have sub-optimum levels of Vitamin D.

    b) They’re fed carbohydrates for breakfast, morning tea, lunch, afternoon tea and supper. They therefore never have any significant serum ketones during the day.

    c) Only people with a Lasting Power of Attorney (LPA) covering personal welfare can give supplements to, or specify a special diet (e.g. ketogenic) for the LPA donor. An Enduring Power of Attorney covers property & financial affairs only.

    O.K. mini-rant over. Cheers, Nige.

  2. Margaret Wilde 8 December 2010 at 6:33 pm #

    What a very encouraging article! Thank you.

  3. traderpaul 9 December 2010 at 3:43 am #

    You might want to take a look at the Dr. Mary Newport’s blog. Her husband has Alzheimer’s and she has been giving him a diet that produces mild ketosis. The key ingredient is coconut and MCT oils.

  4. Sally 10 December 2010 at 9:33 pm #

    Above is a link to a recent article in the New York Times describing how dietary ketosis is used successfully to help children with seizure disorders. Apparently, the diet has been around for a good 70 years or so – long before the advant of anti-seizure meds.

  5. Mauris Emeka 10 December 2010 at 9:33 pm #

    When we speak of so-called ‘carbs’ it’s very important that we specify whether we are referring to simple carbohydrates (like white rice, white potatoes, white flour,macaroni, spaghetti, etc) as opposed to complex carbohydrates (like lima beans, lentil, black eye peas, black beans, garbonzo beans, etc). Readers need to know in no uncertain terms that from a health standpoint there is a big difference between simple carbohydrates and complex carbohydrates. By simply referring to “carbs” in an article the reader can easily come away greatly misinformed.

  6. Misty 11 December 2010 at 12:57 am #

    I can attest to elevated cognitive function with a low carb diet. I suffered for many years with ADHD and compulsive disorders. I was relieved of many symptoms with my discovery of low carbohydrate.

    I notice that when my carbohydrate level is increased, my cognitive function is decreased and most specifically, my even mood is disrupted. I become fidgety, unfocused and lack concentration.

  7. drm 11 December 2010 at 9:33 pm #

    Mauris I agree with you. Any diet which avoids refined carbs and other processed foods is better than the standard 90% processed western diet. Many different natural diets (including those ‘high’ in natural unprocessed carbs) – Ref Weston A Price – are healthly and there is no evidence that low carb is the only good option or the best option for optimum health

  8. slabman 15 December 2010 at 10:17 pm #

    Just one question. Can someone please explain why people in South East Asia who eat lots of rice aren’t all overweight?

  9. LS 28 December 2010 at 9:14 pm #

    The reason WHY people in south East Asia are not overweight even though they eat rice… because the point is more that they DONT eat as much animal protein/animal fat. Yes, rice are “carbs” but the issue is more that they are not consuming as much meat, etc, in their diets, therefore they are not as heavy as people from the West.

  10. jo 2 April 2011 at 12:04 pm #

    Can anyone tell me why the Inuit in the Arctic whose traditional diet until recently was only meat and a lot of fat/blubber never got fat?


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