What is keto diet?
Ketogenic diet (keto) has been showed to be beneficial for healthy people as well as people with many disease conditions. The main principle of keto is that in the state of ketosis we take most of our energy from fat metabolism (fat breaks down into ketones, we call this that we are in ketosis), not from sugar. This is achieved by changing the proportion of the macronutrients in our diet: eating mainly fat as the main source of energy (around 60-80% of the calories), keeping sugar below 50 g per day and moderate amounts of protein (20-30 % of the calories).
The main benefits from keto which I see is more stable mood (as peaks in blood sugar levels can have bad impact on our mood and concentration: for example, by making us more irritable or sleepy), and less food cravings. Every time I am on carbohydrate-based diet, I have moments when I feel hungry and cannot think about anything except for the next meal. During keto diet the urgency for eating at a certain time is much less strong because body adapted to fat burning can easier take energy from stored fat (our own fat tissue). If our main energy source is sugar – the sugar storage is very short and needs to be replenished often. Therefore, regular eating is usually much more needed when we are on carbohydrate-based diet. Eating too much sugar at once is also not a good idea because, if repeated often, it can decrease the sensitivity of the body to use sugar (in more precise terms, decrease the transport of the sugar inside the body cells where it can be used as energy source). This leads to metabolic disorders, such as diabetes type 2.
Keto diet reduces the urge for frequent eating and helps in fasting which has been shown to improve our health (for example immune system and cognitive functions). Humans evolved with limited food supply therefore frequent eating of excessive amounts of food causes stress and inefficiency in our bodies (obesity, cognitive decline, immune system dysfunction).
Here is my personal guide on keto and how I made it work for myself.
Intermittent fasting
Intermitted fasting helps to maintain ketosis. As ketosis develops during a low sugar supply. To keep low sugar, you can combine two factors: (I) keep it low in your diet, (II) intermittent fasting, which is not eating at all during part of the day.
Eating low sugar is quite difficult as sugar is everywhere in the foods. I find it particularly difficult as sugar is also present in almost all vegetables, although in low levels, therefore in a strict keto diet the vegetables consumption would have to be kept to minimum, which I think is not good, because it leads to the necessity of including the supplements for some vitamins and minerals.
Taking supplements is always tricky, for several reasons, mainly because:
· Most of the supplements do not need to pass rigorous clinical research as drugs, therefore we do not really know that much about key characteristics of a particular supplement, such as absorption. In some cases, they can simply be not absorbed in the body.
· Human body is a complex system, therefore adding one component artificially, can disturb the balances between other substances (for example, magnesium supplementation may affect the calcium absorption).
· All drugs we take have side effects. In case of serious diseases this side effects can be counterbalanced by necessity to treat a disease condition, but in case of vitamins and minerals depletion – it may be possible to solve it by adjusting the diet.
Food
[meat] [dairy] [vegetables] [fat sources] [intermittent fasting]
Meat
Poultry, beef, fish. Diversification is the key. Eating only fish is not a good idea given the pollutions with heavy metals. I really look forward for synthetic meat, with lower ethical load and hopefully less polluted.
Keto diet is possible for vegetarians; however, I never investigated this topic. For sure it requires more research and possibly some supplementation as some vitamins (such as B12) are hard to be provided in food without eating meat. But this is not a problem limited to keto diet.
Dairy
Cheese, milk (although in moderation as it also contains some sugar). A good alternative for a cow milk could be coconut mild or unsweetened almond milk.
Vegetables
My favourites, for their fibber content and relatively low sugar content are:
· Asparagus
· Broccoli
· Carrots
· Pepper
· Mushrooms (a keto dream, as they contain no sugar)
· All green leafy vegetables
Fat sources
This is the main food source during the keto diet. Fat is very caloric therefore taking most of the calories from fat does not necessarily mean that this is the part of the meal with the highest volume. It can look quite small, but it can also be a caloric bomb, which is good in this case. I find it important to use both animal fat (as the main source of saturated fat, and fat-soluble vitamins, A, D, E and K) as well as plant fat (as the main source of unsaturated essential fatty acids).
I find butter as the best source of fat (real butter, do not recommend margarine, as it contains artificially modified fats which have detrimental effects on our metabolism). It is important to notice that on keto diet, our metabolism changes and our body becomes very efficient in saturated fat breakdown, which becomes the main source of energy. Other sources could be fat meat (no more skinless chicken breast) or lard.
For the plant-based fat sources, coconut oil is very popular, it also contains a lot of saturated fat. Avocado, nuts, and soybeans contain a lot of fat. I also highly recommend unrefined plant oils, which can be a great source of essential fatty acids necessary for our immune system and proper brain function (such as EPA, DHA, ALA). The choice is wide and not all plant oils contain high percentage of essential fats, but one of the best I found is rapeseed oil, cherry kernel oil and sunflower oil. And of course, famous olive oil.
When talking about olive oil… It is characteristic for so called ‘Mediterranean diet’ popular in countries such as Italy or Greece. There is a lot of research that this type of diet is beneficial for longevity and proper cognitive function. A lot of aspects of this diet are in common with keto and intermitted fasting (moderate calories, fish, olive oil, vegetables).
What is not recommended on keto..
and also hard to exclude from the diet are fruits, pasta, and carbohydrate-rich vegetables (such as potatoes or rice). Even complex carbohydrates, which are generally much more healthy than simple sugar (such as sugar powder, sweets) because they release slowly during the digestion and therefore do not cause a sharp peak in the blood glucose level – are not recommended during the keto diet, unless we will eat them in a quantity small enough to keep the sugar content below 50 g per day. This is however very difficult. With such a sugar level restriction we must be very careful from where we take our carbs, as I think it is good to keep as much vegetables as possible in the diet. Many veggies are low in sugar content but still it is needed to look carefully at the type and quantity of them in a diet aimed for ketosis.
The fruits I do not avoid on keto are:
· lemons (low sugar content, help in digestion)
· tomatoes (sugar content depend on the species)
· berries: strawberries, blueberries in moderate amounts.
Additional factors helping to enter in ketosis are:
moderate exercise (particularly walking or so called ‘Zone 2 training’) and sufficient sleep. This is very generic and helps for many things, but it is never enough to emphasise how much physical activity and sleep is important for our good health. Without these two elements all attempt in other aspects (e.g., diet, supplements) will not help too much. Intense exercise such as weightlifting, is also perfectly possible during keto diet but it requires some additional attention, on how to balance the proportion of fat, sugar, and protein (which is also the case for people for carbohydrate-based diet).
Salt
Last but not least, using salt is also essential during keto diet, as our metabolism changes and salt secretion is increased.
Controversies around keto diet and high fat intake
I think that keto diet can be rich in high quality food, vitamins, and minerals. Dietary fat has been unnecessarily demonized by biased research. This is a sad part of science, that sometimes not very well-designed studies, which are well promoted create wrong believes in society which persist for decades and create unnecessary confusion (such as fake research on vaccines being the basis for anti-vaccine movements).
Additional problem about the research about the fat in our diet is that so called ‘high fat diet’ is used inconsistently in scientific literature. Sometimes it refers to the diet which is rich in both fat and sugar, sometimes it refers to the ketogenic diet, which is rich in fat but not in sugar. This is a huge difference and the metabolic effects of both are completely different. Indeed, I would agree that there is sufficient evidence to admit that high fat combined with high sugar is very unhealthy. But this has nothing to do with ketogenic diet.
Another problem in research is that there is many contradicting evidence, published even in well-established journals. In this way it is possible to find citation for contradicting ideas. I am sure it is also easy to write an article saying that fat is not healthy and that whole-grain food (carbohydrate-based diet) is the most recommended. And there would be some scientific evidence for this as well.
It is difficult to say which diet is the best and compare between different diets because food is something what we use during the whole life and to properly assess its effects on our health, these effects would have to be monitored long term, which is very expensive and difficult to conduct. Another thing is that people differ in many ways, therefore comparing two groups on different diets is not easy as the effects of food can be subtle and other differences between people can make the different diet effects hard to detect. Therefore, I think that controlled studies on the effects of food are very hard to performed. It is much easier to assess the evidence for pharmacological intervention with a drug (e.g., anti-cancer treatment) because the effects could usually be visible in a relatively short time frame and in case of specific pharmacological interventions, we usually have one active substance – which is easier to characterise. Food is complex, and food is not only about macronutrients (fat, sugar, protein) and micronutrients (minerals and vitamins) content but food quality is also affected by environmental pollution, preservatives added or processed food versus raw foods problem. Plus, this is always a mixture of different substances, so it is hard to say what really works and what does not when we are on a certain diet.
General remarks about food
I think the best approach is to follow ‘your own gut’ and see what type of food makes you feel best, try different approaches (such as fasting, keto or whole-grain carbohydrate-based diet) and see what works best for you. Occasional blood test (including checking for triglycerides and various vitamins and minerals) are helpful to make sure we do not harm ourselves. For very specific diet design, or if you do not have too much time to think about it, you can refer to dietician, although I personally think the rule of thumb and using common sense to observe how we feel can be sufficient. There are some obvious principles, for which most of the experts would agree:
· Try to choose food which as little processed as possible (ideal situation is to buy everything fresh and cook it at home).
· Keep variety of different foods, do not fix on one type of meat or particular veggies all the time, because with low food variety it is harder to ensure the supply of all essential microelements.
· Avoid too many preservatives, in other words, foods which can stay in room temperature, or fridge for a very long time. This does not include frozen food, as deep freezing can preserve freshness of the food for a very long time without additional chemicals.
· Avoid simple sugar. As discussion for keto vs. carbohydrate-based diet does not give obvious answers and there are experts on both sides. One thing for which everyone can agree is that it is better to avoid excessive simple sugar (such as sweets, sweetened drinks, using lots of powder sugar).
· Caloric restriction. Obesity is a big problem in western societies simply because of overeating and too much simple sugar content. This problem is independent on the diet applied. Too much food is detrimental for our health. Although not everyone may like the idea of fasting and some people find it too harsh, taking too many calories, which are not balanced according to our physical activity is a leading cause of many widely spread diseases, such as obesity, diabetes type 2, stroke, inflammatory conditions.
At the end, I would like to say that this article is not a medical recommendation, is directed to people who do not have eating disorders or any other medical conditions, as those should be treated with a special care by a medical professional on an individual level.
This is also my subjective opinion, but as mentioned before, it is hard to be objective when we talk about food – even in the scientific world.
Further reading
Best books about keto I have read:
The Art and Science of Low Carbohydrate Living, written by leading researchers in the field: Jeff S. Volek, PhD, RD and Stephen D. Phinney, MD, PhD
Ketogenic Bible: The Authoritative Guide to Ketosis, written by Dr. Jacob Wilson and Ryan Lowery, PhD
Some scientific articles supporting the claims I mentioned in the article:
Mediterranean diet
Obesity
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