What Is The Ketogenic Diet?

The Ketogenic Diet is one which promotes ketosis: a state where the body uses fat as the main energy source instead of carbs, essentially by converting fat (dietary or stored) into ketone bodies.

what is the ketogenic diet

22-Oct 2016, by Lee Sandwith

The state of ketosis can be achieved in several ways:

  1. Diet (nutritional ketosis)
  2. Fasting (fasting ketosis)
  3. The consumption of exogenous ketones
  4. Vigorous exercise.

From everything I’ve read and listened to, I think this explanation from Dr Peter Attia is one of the best:

There are some absolute, bona fide experts out there who are staunch advocates of The Ketogenic Diet and it is work by a number of highly respected scientists which has convinced me to persevere with it, despite having personally experienced some of the negative impacts, specifically on my cholesterol levels (more on this later).

Unsurprisingly, in this ambiguous world we find ourselves in, there are some equally strong opponents. I don’t intend to go into details in this article but if you’re interested a quick Google search will throw up a bunch of articles.

There’s also lots info out there on the history of the ketogenic diet so I won’t spend any time duplicating content here but if you’re interested the glorious Wikipedia is a good place to start.

The top benefits of ketosis?

Interestingly, the diet was first developed as treatment for epilepsy, however, this is is not an avenue I’d like to persue here as I’d like to stay focused on longevity.

There are lots of articles out there sharing details on the benefits of ketosis so I don’t intend on explaining each in detail. For further reading, there’s an extremely nice article from Authority Nutrition outlining the basics of the diet and one focusing on the top 10 benefits. There’s also another on Livestrong which may be worth a read.

For those of you who like things in bite sized chunks, here are what I believe to be the top longevity and lifestyle related benefits ketosis and the ketogenic diet:

  1. Better control over appetite and hunger
  2. Increased cognitive ability
  3. Weight loss
  4. Improved lipid profile: Triglycerides and HDL cholesterol
  5. Optimisation of blood sugar and insulin
  6. Potential treatment and cure for type 1&2 diabetes
  7. Potential cancer prevention and treatment

The key immediate benefits which have encouraged me to persevere are the first two. When I’m in ketosis I have much greater control over my appetite and I feel like my brain is super charged.

The effect the diet has had on me from a cognitive perspective is simply astounding. Obviously this is a sample size of one, but there is solid research out there to back up adding cognitive enhancement to the long list of potential benefits.

In addition, my interest in ketosis is maintained due to the potential long-term benefits, specifically the potential for it to fight cancer: I’ve seen first hand what cancer can do and I definitely don’t want it!!

Despite what we have been lead to believe, the chances are that cancer is not a purely genetic disease but something which develops through external factors with glucose playing a major role (potentially). Knowing that the ketogenic diet has the potential to prevent cancer has really caught my attention and hopefully it will catch yours too.

In summary, The Ketogenic Diet can offer some immediate benefits such as satiety management, enhanced brain function and glucose optimisation, and it can lay a strong foundation in terms of preventing nasty diseases such cancer.

How to achieve nutritional ketosis

Similar to my 40-20-20 approach outlined in my last article, nutritional ketosis is achieved by getting the balance between the three macronutrients right.

The perfect balance varies from individual to individual but broadly we’re talking about keeping carbs very low, consuming a moderate amount of protein and getting the remainder of your calories from fat.

The traditional ratio is 4:1, meaning 4 parts fat, 1 part coming from a combination of carbs and protein which normally results in 80-85% of calories coming from dietary fat.

Take a moment to let that sink in.

85% fat!

In addition, it is normally also necessary to target less than 50g of carbohydrates per day, and to limit the amount of protein as too much can cause something called gluconeogenesis which essentially converts protein into glucose and can keep you out of ketosis.

Achieving these ratios will pretty much guarantee that you enter ketosis within a few days and as your body starts to adapt over time – referred to as keto adaptation – you can easily reach moderate levels of ketosis within a day or two.

To add some complexity, the sources of each macro are also important. For example, the fibre content within the carbs you choose is very important for a number of reasons and the type of fat is a factor too.

I’ll come back to these points in a later article but to close off on this section listen to how an expert explains different approaches and some of the nuances, this time Dr. Dom A’Gostino on Rhonda Patrick’s podcast.

For me, getting carbs below 50g is the key trigger but this varies from person to person so there’s no hard and fast rules. Also, as Dr. Dom intimates in that excerpt, the good news is that nutritional ketosis can also be achieved by following a somewhat less strict diet than the 85% fat approach outlined above essentially by using what has been coined a modified Atkins diet (or modified ketogenic diet) where the carbs are slightly higher, fat lower.

What the ketogenic diet is not

I was sold the concept of the diet by a close friend who has been an advocate of a low carb approach for some time on the grounds that if your diet comprises mostly fat then your body metabolises calories in a different way, thus enabling you to consume more calories than normal and still lose weight.

Although this defied all logic, this was a very attractive concept.

Second, it was sold that a low carb diet can also help reduce cholesterol and have major benefits in relation to insulin sensitivity, the former of which really appealed to me as my lipid profile was something I was slightly concerned about.

Whilst both of these things may be true for a percentage of people, it’s certainly not true for all and in my humble opinion the diet should definitely be approached with caution.

I’m testament to this as after 3 months of following a strict ketogenic diet, I ended up gaining weight and my LDL Cholesterol levels sky rocketed to what is considered dangerous levels in the medical community. Given that heart disease runs in my family, this freaked me out beyond belief and took me on a completely new journey of discovery.

Fear not, it turned out quite well and I plan on sharing everything I have learned.

In summary, in my experience:

  1. The ketogenic diet will not allow you to defy the laws of thermodynamics (you may be able to consume slightly more calories but the calories in/out model still applies)
  2. There’s a good chance that you will experience elevated cholesterol – according to some experts this may affect up to  around 33% of people who try the diet and it should be something to be concerned about.

With all that being said, I still believe that the positives of the diet outweigh the negatives. I’m still experimenting but the benefits I have experienced have been pretty astounding and I haven’t given up on it yet.

Related articles and further reading

Image courtesy of meandmydiabetes

  • Excellent reading Lee. I’ve been on a Keto diet for around 8 days and nothing happening so far. Had my blood test again today as I also have high cholesterol , LDL etc and the results of the test today showed it has all increased. However my doctor said the results would’t show up so soon anyway and recommended I simply reduce the saturated fat if continuing on the Keto diet! On a positive side I was Diabetic 2 and for the last 5 days my blood sugar has come down to normal. I also believe it still comes down to portions and balance! Thanks again Lee.

    • Hi Toni. Thanks for the feedback! Writing articles like this is quite a time consuming endeavour so getting positive feedback is very encouraging, thank you. How is the keto diet working for you now, should be about 13 days right? Initially I found that it took about 5 days to get into ketosis and I always experience the satiety control benefits almost immediately. The cognitive enhancement thing doesn’t really kick in for me until I hit around 1.2 mmol/dl; are you monitoring your blood to test whether you’re actually in ketosis? Everything sounds great re your blood sugar, that’s a major positive, congratulations! On your cholesterol, it’s an interesting subject and something I’ve been studying vehemently of late. I’ve just finished an article in which I share my latest results and they have been so crazy that you may get some piece of mind on yours 🙂 you can check it out here

    • Hi Toni. Thanks for the feedback! Writing articles like this is quite a time consuming endeavour so getting positive feedback is very encouraging, thank you. How is the keto diet working for you now, should be about 13 days right? Initially I found that it took about 5 days to get into ketosis and I always experience the satiety control benefits almost immediately. The cognitive enhancement thing doesn’t really kick in for me until I hit around 1.2 mmol/dl; are you monitoring your blood to test whether you’re actually in ketosis? Everything sounds great re your blood sugar, that’s a major positive, congratulations! On your cholesterol, it’s an interesting subject and something I’ve been studying vehemently of late. I’ve just finished an article in which I share my latest results and they have been so crazy that you may get some piece of mind on yours ? you can check it out here – http://ingfit.com/the-ketogenic-diet-and-cholesterol-part-1/

      • Hi Lee,

        Thanks for your reply. My cholesterol was also off the charts before Keto, so this is a little concerning. My last check a few days ago was: total Cholesterol: 265 – HDL 36 and LDL 182 It has increased from around 4 months ago although my doctor informed me the this new diet wouldn’t show in only 7 days from a blood test. She also recommended I reduce the saturated fat and increasing more e.g. olive oil etc

        I can only assume I am in Ketosis as I cannot get any Keto testing kits here. I reside in Thailand and have tried everywhere including Boots and emailed Bayer (they have an office here) but didn’t reply to any emails sent. I was also told that there’s a good chance that if I try to have a kit posted here it will be sent back due to import rules!

        Around 4 days after starting the Keto diet I was regularly visiting the toilet and felt really bad for a day including flu like symptoms so I assume it’s working. My weight has slightly dropped.

        Reducing my blood sugar in a short time was awesome! I do find it a little difficult walking past my local bakery but on the other hand it’s great to have a lamb chop etc unlike my previous boring diet 😉 Watching my wife drink my Guinness was the hardest but I will persevere! 😉

        Last year my cholesterol levels were also off the charts and believe it or not almost double yours! I had skin problems and was seriously overweight due to extreme LDL levels. I went on the typical diet, exercised and reduced my weight by 12 kilos in 3 months. I could not reduce my blood sugar though! In almost a year I have not increased in weight and decided to become even healthier by going Keto to reduce even more.

        Although Keto makes sense, sadly a lot of videos, websites etc are sponsored hence I think have sold out! There’s one video from a famous doctor that had him saying ‘this is a top secret you mustn’t share and only for you’ on a YouTube channel! After this I stoped watching and found your blog most real and I really believe now as you wrote the saturate fat should be reduced! I recently cut back on the saturated fat similar to you and until my next blood test (2 months) will not know! Now to find those Keto strips and I will keep following your posts. Excellent reading.

        • Hi Toni,

          I am in a similar position to you as I live in Dubai and things like keto strips are very difficult to find. I used Amazon Shop & Ship and got the urine strips (Ketostix) and the Abbot Blood Monitor; the strips for the latter are expensive but the gold standard.

          I know what you mean about the amount of confusion out there. That’s one of the reasons I started the website and what encourages me to keep going. I think it’s difficult to find true objectivity as most people are trying to monitise their projects. Me included if I’m completely honest but I it’s more important to keep everything honest in my opinion otherwise there is no credibility.

          Your cholesterol numbers sound fine to me. Suggest you find a hospital which can do an NMR as the important number is LDL-P, not the LDP-C you’re getting from the standard test.

          Where are you in Thailand btw?

          • Hi Lee,

            I live in Bangkok although I’m from the UK. I don’t know why but whenever I try to buy from Amazon they say they don’t ship to Thailand. I’ll look around and perhaps take a chance from ebay.

            Respect that you would like to monitise your project but keeping it real.

            I don’t believe a Keto diet is an ‘eat all things fat’! I believe we should still regulate our portions! This is what interested me in your 40/20/20 It makes sense!

            My diet plan is to remove all the carbs, sugar etc but eat proteins with healthy amounts of fat! I’m not frying everything in butter etc as some wrote. We’re all genetically different however for myself I was never overweight etc until around 7 years ago! I started eating in 5 star hotels gorging on buffets! I don’t think it will be too difficult to bring my weight back down.

          • Haha! The buffets will certainly do it 🙂

            Totally agree with you about keto being more complex than just eating loads of fat, especially when it comes to saturated fat which is what I suspect may be impacting my cholesterol. I’m still getting around 100g carbs per day and staying in ketosis and agree that portion control is important; people who argue that calories don’t matter are simply wrong, you can’t defy the laws of thermodynamics 🙂

            Check out Shop & Ship, I believe they have just started in Thailand. If you sign up, you can order anything from amazon.co.uk and you provide a UK address which routes to an Aramex address, they then forward the package to you in your country. You have to pay for the service but it’s quite reasonable and awesome for getting the obscure things that you can yet get locally.

            Love Bangkok, major Thailand fan ?

            Keep in touch. If you sign up to my email list I’ll let you know when the next article comes out which I think you’ll be very interested in.

            Best, Lee

          • Hi
            Apologies for the late reply. Thanks for the Aramex tip but I discovered I can get these products on eBay. For now I ordered some Baya Keto strips. I’m staying with my reduced carbs etc but increased my omega-3 intake. I will stay in touch and subscribe. many thanks for your time.

            Last 3-4 days having a crazy time in the gym! I’ve never had so much energy especially after a few hours!! This can’t be from glucose!!

          • Great stuff Toni, keep me posted on how things go 🙂

          • Hi Lee – well 4 months later since our last chat and 2 blood tests reveal my Keto diet failed me over a period of 5 months!

            My blood test today: Total Cholesterol 268 – HDL: 42 – LDL 205

            5 Months before Keto: Cholesterol 265 – HDL: 36 – LDL 182

            The only thing that reduced and continues to do do is me Triglyceride from 507 – 174

            Over a year ago I changed my diet to salads, fish, etc and reduced to: Cholesterol 211 – HDL: 55 – LDL 151

            This appears to be the best option and if I reduce carbs and perhaps go back to this diet would get better results. However, today my doctor prescribed me Crestor statins which appear to have some serious side effects and I’m sitting here thinking about to take them or not!

            During my Keto diet over the last month I reduced the fat and portion sizes including just 2 meals a day (couple of times a week) Nothing worked and I’m taken back by this. Any advice?

          • Hey Andy,

            Great to hear from you!

            You sound a bit worried about this so let me reassure you a bit. Firstly, from what I’ve learned, high cholesterol may be an issue, however, at the same time it may not and a cholesterol result alone should not be used to take a decision on statins.

            Let me explain why.

            The most important thing to understand is that high cholesterol does not necessary mean atherosclerosis which is essentially what we’re talking about when we discuss heart disease risk. If you’re really concerned, you can actually do a test which tests for plaque build up in the arteries. If there’s no plaque build up then there is no issue.

            Next, there are a bunch of other factors which need to be considered, for example, inflammation, LDL particle number, ratios between certain sub-particles.

            Further, I’ve just learned recently (from a guy called Dave Feldman, worth looking up) that what you eat within the few days before a test massively impacts the results!!

            Lastly, if the keto diet is the only variable between tests, then you can quite confident that the diet isn’t the issue and there may be a number of other benefits which may keep you on the diet. If you’re following it properly, your inflammation if likely tonne very low which reduces the heart disease risk: according to some experts, if there’s no inflammation, there’s no plaque build up.

            Anyway, I’ve recently published a bumper article on all of this stuff so please head over there and take on board as much as you can to support your decision on whether to start those statins or not. It’s very comprehensive so will take some time to review and I’ve included links to lots of other resources.


            Finally, there are many many healthy people with cholesterol much higher that 268 so you’re not alone. Mine’s always around 300 and I’m not even entertaining statins as I’m still experimenting with drug free interventions.

            Hope that helps.

            Best, Lee

          • Hi Lee – once again thank you for your time and sharing your knowledge which is truly appreciated. I’ve decided to take the route of introducing a few complex carbs e.g. oats and swapping the meats to mostly fish high in omega 3. I will also attend the gym twice a day for cardio and weights (strength)

            I was also recommended to replace the doctors prescription of statins with choles-bloc (plant sterols) which is natural to help lower cholesterol!

            I would also like to seek out a hospital to test for atherosclerosis even though I would still like lower cholesterol numbers. After 5 months of Keto it was daunting to find such high numbers and to be honest perhaps I ate a little too much fat e.g. lamb, pork!

            Keto reduced my diabetes and triglycerides and I believe the solution which may work for me is the above. I’ll keep you posted. I’ll try anything apart from Statins!

          • Sounds good Andy, good luck and keep in touch!!

          • WOW I just saw some Dave Feldman videos!! This is a whole new perspective!! Thanks!!!

          • No problem! I’ve reached out to Dave and he’s very responsive and supportive. I’m not too keen on the 3 day protocol as I don’t think that’s a permanent solution but it does show how complex the whole thing is and that there’s a lot of ground to be covered before statins are prescribed. As a first step, I would get your inflammation checked (CRP) and your ApoB. Run your ratios to see if there are any flags there and if there are, consider getting the CIMT test done. Pretty sure you’ll be able to sort one of those in Bangkok (that’s my next step). Also, I would change your GP; try to find a GP or Cardiologist who is sympathetic to the ketogenic diet AND is a bit more up to speed on ratios, particle size etc. If you find a good one in Thailand, please let me know as I’ll be coming over for some tests shortly (specifically the CIMT which I can’t find in Dubai). Cheers, Lee

          • Hi Lee – thanks and this will be my next step! I’ll seek out a hospital next week and let you know. My GP was pretty sympathetic and knew I was on Keto but as the cholesterol kept rising suggested it was hereditary and to go on statins. This recent info has changed my perspective although I would like to have lower cholesterol numbers as with my first diet.

            If you come over here and have time do look me up as me and my wife would be more than happy to take you to some great locations.


          • To be honest, sounds like your GP is a bit out of touch. My last one thought I was crazy for going on a high fat diet and tried to persuade me to go low fat again!! Painful conversations. Anyway, keep in touch. I will hold you to that offer next time I’m in Thailand 🙂

          • Hi Andy,

            Just wanted to give you an update. I had a blood draw last weekend and my Total C was down to 198, LDL 112 which is the lowest score I’ve ever had!

            I’m getting two more blood draws in the next two weeks as I’m doing another self experiment looking at two really specific variables.

            Will be posting my results soon 🙂

            Best, Lee

          • Hi Lee – that’s fantastic news! What was the time period between this and the last test? Day’s, weeks, months? I have reduced my saturated fats (increased/replaced with olive oil, fish, omega-3 etc) and exercise mostly twice a day including weights! My cholesterol 268 was on 29th August so I’m not sure how long to wait for a re-test? The only carbs I increased were oats in the morning with berries and nuts! Left the statins on my desk!

          • If you buy in to Dave Feldman’s protocol (which I do), what you’ve eaten in the 3 days running up to your test is the key thing. Essentially, I went high carbs again and cut out coffee before that 198 test. There’s loads of emerging evidence about coffee being a factor which can increase LDL. My coffee consumption used to be off the charts, in fact, the only anomaly in my normally healthy diet. I’ve been keto all week so I can compare high carb v low carb (low sat fat), and I’ll get another test this Saturday. This will be my baseline. Then next week, I’m going to keep the diet exactly the same but add coffee back into the mix. If I can narrow it down to coffee I’ll be delighted as I really want to stick with keto. Are you a coffee drinker?

          • That’s interesting Lee as I was a coffee drinker up to my last blood test. I now drink more water, green tea and a little camomile tea! One of the most important factors is the vast differences in blood results in such a short time! However, I was having blood tests every 2 months which steadily climbed and vastly over the last 2 months. I also read your other posts so I think I’ll book a blood test at the end of next week!

          • Even on Saturday my Doctor was bringing statins into the conversation! It’s very frustrating as I’ve proved that cholesterol management not a long term endeavour (i.e. it’s not about making a change and monitoring after 3-6 months). Your test is simply a snapshot of cholesterol particles in your blood stream at that point in time and it’s clear that there are major fluctuations over short periods. This is the basis of Dave Feldman’s work and something that was first drawn to my attention by Peter Attia (one of his articles I think). I truly believe that it’s just a matter of finding which factors are most influencing the results; and you do that by being pretty controlled in what you’re experiments (meal plans, supplements, exercise) and pulling at different levers. Anyway, I should be able to post my results on Sunday next week so it will be really interesting to see if it’s down to low carb / keto or something else. This is the tightest self-experiment I’ve done yet: I’ve been eating exactly the same thing every day, give or take 🙂

          • I’m looking forward to seeing these results as well as my own! There are only a few posts like yours that ‘demonstrate major fluctuations over short periods’ which needs serious investigating!! Keep up the good work. By the way – I hate blood tests LOL

          • Thanks Andy, that means a lot 🙂

          • Hi Andy, The results are in! Cholesterol gone up from 198 to 232 following a week on keto with no coffee, not a major increase!! Next test on Wednesday to isolate coffee as a variable!! The next 3 days is all about consuming much coffee, happy days 😅

          • Mine went up around 35 in 4 months but it still demonstrates it can change of days and weeks! It’s trying to find the culprit that increases cholesterol! I’ve had no saturated fat for almost 2 weeks changing to healthier oils but still kept my carbs low! Blood test coming soon! LOL

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