One of the most common questions we get is what kind of diet our customers should follow. Of the various diet plans and options out there, the one that comes up the most is the keto diet, or very low carbohydrate diet. Below we look at what the keto diet is; what a keto diet looks like on a day to day basis, and whether someone should consider it as a way to lose fat or recompose. We will also cover issues of performance and health.
What is the keto diet?
The keto diet is a low-carb, high-fat eating plan that has first gained some notoriety in the 1970s with ‘Dr Atkins’ Diet Revolution’ book. It caused such a stir at the time because Dr Atkins claimed that a person could eat any amount of food and still lose fat on the keto diet. These claims were later retracted, and keto hit the news again in the 1990s with the reissue of ‘Dr Atkins’ NEW Diet Revolution. The diet is based on the premise that carbohydrates (including sugars and grains) stimulate the secretion of insulin, a key hormone that helps the body store fat amongst other things. When your body runs out of carbs storage, you are forced to use body fat as the primary fuel source. When burning fat, in the absence of any stored carbohydrate, the body produces by-products of the fat-burning process called ‘ketone bodies’. Therefore, because this style of eating is intended to create ketones, it is referred to a keto-genic (genic is just Greek for ‘giving birth to’ – thus ‘gene’, ‘genesis’ etc). The key thing with keto is that you try to eliminate carbohydrates altogether. In reality this isn’t possible, but many keto advocates will attempt to keep carbs below 20g.
Is Keto the same as Low-Carb?
Keto is the very extreme form of low carb diet, but the two forms of diet are not the same. Low carbohydrate diets range all the way from around 40% of your daily calories coming from carbohydrates, right down to as little as possible – which is theoretically ‘keto’. In most low carbohydrate diets the focus is on measurement and control of carbs. On keto the key measurement that’s performed is daily (or more frequent) urinalysis or blood test or (more recently) breath testing to see if the body is producing ketones. It works on the assumption that carbs have been all but eliminated from the diet, so they don’t need to be measured per se.
What does a keto diet look like on a day to day basis?
On a day-to-day level, keto adherents will be eating a lot of meat, and (hopefully) green leafy vegetables and broccoli. They may be adding oil to all their food and may be having nut butters and other high-fat snacks (but without the bread). The food will be heavy and high on protein and fats (being the other two macronutrients). Breakfasts may be hot. Eggs, bacon, sausages are all fine – but hold the toast and beans. In restaurants they may steer away from Asian foods which tend to have a lot of hidden sugars and will likely go for the plainest meatiest dish on the menu. They’ll be asking their waiter to remove chips, potato (sweet or otherwise), bread, rice, noodles. With the availability of very low carb food substitutes, at home they may be having noodles or rice made of Konjac flour, or heart of palm but for some even this may be too many carbs. Desserts may just not exist at all, or some adherents may have one small square of 90% cark chocolate. I once knew someone who would prepare a dessert of 0-calorie jelly and double cream. All in all, it’s pretty restrictive.
In what circumstances might the keto diet be helpful?
A keto diet may help to reduce insulin resistance and increase insulin sensitivity. With the aim being to keep insulin low, this may have some beneficial effects on this and blood sugars in general. I may also be helpful for adherence in the specific case that all the foods that a person really likes are these heavy fatty, carb-less foods. There are of course some key medical areas in which a keto diet may be helpful. The diet was originally developed as a treatment for some forms of epilepsy. Ketones are a unique energy source in that they can cross the blood-brain barrier, and so can be used to fuel the brain. There is an evolutionary theory that the body developed ketones in order to serve this very purpose in circumstances of low availability of plant foods. In general people who are well adapted to the keto diet, often praise it for the smooth even mental energy and focus it gives them. By not being subject to the vagaries of high and low blood sugar, ketone advocates will say that they work and think better on keto. The nature of the food will also keep you fuller for longer, so if you find yourself feeling hungry every couple of hours, maybe keto could show you what long-term satiety feels like.
The cons of the keto diet
The first and most obvious downside of the keto diet is how restrictive it is. In a restaurant it will be near impossible to find a meal that doesn’t need to be modified in order to be somewhat compliant. And even with modifications, the threat of hidden sugars is ever present.
The second is the the days referred to as ‘keto flu’. In the first few days of adopting the diet, the body is having to adapt to an energy source it is not accustomed to. It may not be efficient at this and may in effect be ‘waiting around’ for more carbohydrates to enter the system. During this time the person feels especially lethargic, low motivation, low energy, and often headaches and other symptoms may emerge. Once the person starts to keto-adapt these symptoms will usually subside.
Lastly, keto is a huge problem because it is a bit ‘all or nothing’. If you have a single big carb meal, this will certainly be sufficient to kick you out of ketogenesis and may even refill some lost glycogen. If this happens that means that it may even mean you’ve lost ‘keto’ status for another 5 days, and another period of keto-flu is ahead of you to get back into it. The fact that the diet can’t really withstand even small lapses in adherence is a big problem, psychologically. If someone has a carb meal, they often will throw the diet to the wind and carb up while they can, and ‘restart on Monday’. This approach is hugely problematic and ultimately defeating for any consistent or concerted fat loss effort.
Is the keto diet good for fat loss?
The ketogenic diet has been proven to be an effective weight loss tool in clinical trials, but the diet must be properly followed to result in weight loss. The key thing to note however is that, as anyone who has followed keto can tell you, in the first week after the keto flu, you lose sometimes 2-3kg straight off the bat. This can be very encouraging, but we also know that this weight loss is pure water. Every molecule of glycogen (stored carbohydrate) in the muscles and in your liver, attaches to two molecules of water. When you deplete your glycogen, the water is released, leading to the 2-3kg of weight loss. In DEXA terms, this will mean an instant loss of 2-3kg of lean mass. So, it’s important to keep consistent between scans. If you take your baseline scan already in keto, you will need to take your update scans also in keto to get a like-for-like comparison.
In longer term studies however, the results of keto dieters did not exceed that of other forms of diet when equated for calorie deficit. Keto is therefore not a magic bullet of any kind for fat loss. Furthermore, the extreme restriction of lifestyle that accompanies keto may make adherence to and consistency on the diet plan very difficult.
The final verdict: Should you follow the keto diet?
There may be a limited number of circumstances in which the keto diet may have some uses, but in general we don’t like how all-encompassing it needs to be to be effective. Ultimately it will be the number of calories you consume on the plan that is the determinant of the amount of fat you can lose. If we ever choose to deploy a keto plan (and it is unlikely we would prescribe something so restrictive) it would be for a very particular purpose, and probably be for a short amount of time.
As we are all about sustainable ways of eating and long-term eating for health rather than diets, we don’t really like how many adjustments people have to make to their lives in order to follow this plan.
That said, if someone is dead keen on going on keto, we will of course support them, but we will still come back to the fundamentals of a sustainable calorie deficit while eating a wide-ranging nutrient dense and interesting diet. And time and time again, we have the DEXA results to show that this approach works. Every time.
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