What is the keto diet?
by Tobias • 6 minutes read
Last updated: 29 Aug, 2022
Anyone that has dabbled in dieting has no doubt heard of the ketogenic, or keto diet. For those that haven't and those that would like some more info of the pros and cons, read on as we deep dive into this trending way of eating.
The main purpose of the keto diet is to get your body to burn ketones for fuel instead of carbs. To do this you will need to restrict carbs to a very low level, the actual number is hotly contested, with some saying 50 grams per day and others saying as little as 10 grams per day, as with most nutritional advice it is personal to you. If you take away carbohydrates and sugars, your body and primarily your brain, will have to find an alternative fuel source. A little known fact is that the brain is responsible for burning about 500 calories a day, or about 20% of the calorie need for an average man. These calories are normally used up in the form of glucose which is made as the body breaks down carbohydrates. Essentially turning complex sugars into simple ones. In the case of potatoes, turning starch into glucose.
When the brain detects that insulin levels are very low, due to the lack of carbohydrates, it sends signals to the liver to massively increase the amount of ketones that are being produced so that they can be used as a fuel source instead. The two main ketone bodies are acetoacetate (AcAc) and 3-beta-hydroxybutyrate (3HB), while acetone is the third. The acetone is the cause of the unusual side effect of a "chemical smell" in the breath and urine of someone in ketosis.
Ketones are made from dietary fats, so whilst the keto diet is often referred to as a "low carb" diet, it would be more accurate to say that it is a "high fat" diet. Without these fats the body will never go into ketosis and you could suffer from malnutrition related illnesses.
What to eat on the keto diet
As discussed above the ketogenic diet is a high-fat, low-carb diet. This means that you will need to reduce your intake of carbohydrates down to a very low level. As mentioned above, the actual figure varies, depending on your body size, if you are tall man, aim for the higher end of the spectrum, but never above 50g. If you are a petite woman then you will need to restrict your carbs to almost zero.
Be aware of the mention of "net carbs" in keto advice, there is some debate about the validity of this idea but essentially the thought is that fibre in food negates some of the carbs. As fibre is listed as a carb on nutrition packaging, but is not broken down by the body, it should be discounted from the calculation. To put it simply, total carbs - fibre = net carbs.
If you ever hope to enter ketosis then you will need to completely abstain from all starchy carbs such as potatoes, pasta, bread and root vegetables and a major reduction in sugary vegetables and fruits. Keep a track of your net carbs, which you may inadvertently eat through foods like peas and carrots. Even a relatively small amount of carbs could push you out of ketosis.
Someone on the keto diet should aim to eat a large amount of proteins and good fats. Examples of proteins suitable for ketosis are steak, high-fat minced beef, fish and seafood. Keto friendly good fats can be found in nuts and seeds, avocado, fish and seafood. A bonus to the keto diet is the liberal use of fats and oils such as olive oil, coconut oil and butter. All the above foods are high in protein and good fats, whilst containing almost zero carbs.
There are some simple switches you can make to increase the likelihood of entering a deep state of ketosis. You should replace white and milk chocolate with dark chocolate, replace crisps (chips) with seeds and nuts. There are specific keto-friendly breads and pastas on the market, but the jury is out on their effect on the ketogenesis within the body.
The main benefit that is reported from the keto diet is weight loss and there are a large amount of studies to back this up. Due to the body not receiving carbs and instead burning fats, if you monitor your total calorie intake and only eat a moderate amount of fats, the rest will need to be burned off your body and in that way you will burn body fat and lose weight. Studies show, in the short term at least, that this is the case.
The keto diet could potentially help fight cancer by reducing tumour size. Studies show that by combining a ketogenic diet with standard chemotherapeutic and radiotherapeutic options may help improve tumor response, although more research is needed.
With such a large reduction of carbohydrates, the dieters insulin sensitivity is sure to change. In fact, it's the lack of insulin that actually triggers the body to enter ketosis. This in turn could benefit those with diabetes and help them maintain a consistent blood sugar level. In some anecdotal cases the keto diet has actually been reported to have "cured" Type-2 diabetes.
Due to the high fat nature of the keto diet, opponents suggest that it could lead to health issues such as heart disease and stroke, although several studies suggest that in fact, the opposite is true.
Another issue with the keto diet is that a lot of people that recommend the diet are not actually in ketosis. Ketosis is caused by spending 10-14 days eating a very low carb, high fat diet. Some people are not consistent with the diet and instead only benefit from the reduction of calories that normally goes hand in hand with any carefully monitored diet. To be sure you are in ketosis you should by a ketone breath meter or ketone test strips to test at home. Typically the breath meters are more accurate but also more expensive when compared to the test strips
Tip: There are new studies being done all the time on the long term effects of the keto diet, always let your doctor know if you plan to try the keto diet.
The keto diet has been shown to be effective in maintaining a healthy weight at least in the short term, and there are also other potential medical benefits too. The long term effects are still being studied so it's not entirely risk free. Compared to most diets however, there is a large body of science to back up the claims. As long as you consult your doctor or healthcare practitioner before you start the diet then it should be perfectly safe and effective.
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