Does Ketosis Really Work For Weight Loss?

Trendy diets come as quickly as they go, and the award for 2017’s biggest diet fad will surely go to the Ketogenic Diet. Already associated with the usual line-up of fashion-conscious celebrities like Kim Kardashian and Gwyneth Paltrow, the Ketogenic Diet is an unusual approach to losing weight that favours eating fat above all else.

What is the Ketogenic Diet?

This relatively new diet enjoys a rather odd origin story as a 1920’s treatment for epilepsy in children. Though the reasons why are still poorly understood to this day, doctors discovered that forcing the body to enter a state called “ketosis” apparently helps to reduce the frequency of seizures. As a side effect, the same state also apparently causes noticeable rates of weight loss, which led some enterprising groups to begin marketing the whole process as a “revolutionary weight loss plan” in the last few years.

But what is ketosis anyway?

Ketosis is a process that takes place when the body has run out of carbohydrates and instead begins to use fat stores as a source of energy. It is so named because of the way the liver begins to transform fatty acids into something called “ketone bodies”, a set of molecules which then provide the necessary energy. These ketones can effectively replace carbohydrates as the body’s main source of fuel, meaning that we can technically run entirely and directly off of unwanted fat stores.

Those familiar with dieting may recognise the phrase “ketosis” from an earlier program called the Atkins Diet, which advised dieters to target ketosis as a key goal of the plan. The main difference between the Ketogenic Diet and the Atkins Diet is the severity of the plan; Atkins only recommended entering into mild ketosis as a first stage only, whereas this more extreme approach aims for a much more dramatic change.

So how can you achieve ketosis?

To force the body to enter into this unusual state, dieters must consume far more fat than carbohydrates or protein. Depending on who you ask and which plan you are following, dieters are expected to ensure that 75-90% of their daily calories come from fat. The rest may come from a combination of protein and carbohydrates, although most plans recommend limiting carb intake to just 10-30 grams a day.

The effect this has on a normal diet is dramatic. To consume such huge quantities of fat without consuming protein, most ketogenic dieters end up pouring butter or heavy cream over everything else. Fruit, dairy products and almost anything resembling a normal meal are generally impossible to include. The real culprit here is the limitation on carbohydrates; even at the upper limit, 30 grams of carbohydrates will only allow most to have a single slice of bread or a piece of fruit.

Most ketosis-based diets are dominated by oils, nuts, butter, cheese and a limited amount of high-fat comfort foods (like bacon or kebab meats). Vegetables (not fruit) can be eaten in moderation, although some celebrity practitioners have slightly altered their approaches to allow for relatively more healthy greens. Those following the diet as recommended must be sure to take multivitamins or other supplements, as the lack of healthy nutrients can cause serious complications (more on this later).

It’s important to remember that this diet is intended to produce a very specific effect, so tampering with the rules isn’t often recommended. Telling whether the body has reached “optimal ketosis” is actually very easy, and many practitioners rely on feedback to see whether they are on the right path. Using a ketostix (a specialised medical needle kit which is available in some high-street stores or pharmacies), ketogenic dieters can measure their blood ketone level. Practitioners recommend having 1.5-3mmol/L of ketones in the blood to achieve “optimal ketosis” and maximal weight loss results.

But here’s the killer question: does any of this help you lose weight?

It does actually, although there is disagreement as to why. Some make the common-sense argument that as the body is starting to use fat as a fuel source, it then stands to reason that the body will begin burning fat more rapidly. Others have pointed out that the real source of weight loss may actually be down to fewer calories consumed; the highly restrictive nature of the diet means that few meals are practicable and appetites tend to dip. It turns out that consuming your weight in butter may actually dampen your enthusiasm for eating at other times in the day!

Due to the types of foods that tend to be allowed on the Ketogenic Diet, some dieters may also find themselves eating healthier fats that are less associated with weight gain. Many of the carbohydrates we consume on normal diets are major sources of sugar, salt and processed ingredients. If these are swapped out for the kinds of healthy fats we see in nuts, certain cheeses and fatty fruits like avocado, weight loss could take place for quite obvious reasons.

Some of the weight loss may also be temporary. Some have suggested that a lot of the weight loss experienced during ketosis may only be water weight, as carbohydrates hold far more water whilst in the body than fat. Some researchers have suggested that the largest part of the weight loss experienced during ketosis is urinated out in the earliest stages.

So, it works! What’s the problem then?

Where do we start? The most obvious issue with the Ketogenic Diet is that it simply isn’t safe. Ketosis is thought to cause a number of serious issues over the long-term, including liver damage, muscle wastage, hypoglycaemia, nutrient deficiencies, weakened bones, chronic head pains and dizziness, balance issues, kidney stones and more. Most obviously, the over-reliance on consuming fat can also cause cholesterol levels to skyrocket, which massively increases the chance of having high blood pressure and heart disease.

There are also problems that will emerge straight away. Ketosis is ultimately your body’s emergency measure, and no-one can really function properly whilst in it. Researchers have noted an extreme dip in performance in the gym from athletes in ketosis, with many unable to perform at their expected level in strength training routines or in cardio-based routines. Exhaustion is a commonly-reported side effect of ketosis, as well as digestive problems related to the lack of fibre that’s permitted on the diet. Though less serious, those in ketosis will also notice impossible-to-solve body odour and bad breath problems, both of which are directly caused by the higher rate of ketones in the blood.

Worst of all, ketosis will help most to lose weight in the short-term, but is almost inconceivable as a long-term approach to weight loss. The main problem is that this unnatural state absolutely destroys a normal metabolism; when eating habits become normal again, the body tries to store fat at far higher levels than normal as a means of defence against starvation. This change can cause permanent damage, as the body forever attempts to protect itself against the possibility of ketosis happening again.

All of this is only possible if the dieter actually manages to achieve “optimal ketosis” in the first place. The Ketogenic Diet is possibly the most inflexible diet out there, and has reportedly been very hard to maintain for most dieters. Most anything resembling a normal meal is not permitted, and a fat-only diet must always be stuck to rigidly in order for anything to be achieved. Few dieters could conceive of eating this way for the rest of their lives.

So in conclusion…?

The Ketogenic Diet is extreme, and like most extreme things it represents a rather daft approach to a simple problem. Although it can cause weight loss, it has to be one of the hardest eating plans to stick to, and poses the risk of causing serious health problems and permanent damage to the body’s metabolism. After all, ketosis is the body attempting to survive in the face of extreme pressure; inviting this state on for the sake of weight loss smacks of overkill.

As always, the best way to approach weight loss is through boring old moderation. Stick to a diet rich with fresh and healthy vegetables, lean meats and a light serving of carbohydrates, and practice calorie-counting and portion control to ensure that you don’t overeat. Your diet may be a little less fashionable, but your weight loss will come with a lot less fuss and nonsense!

Disclaimer: Our reviews and investigations are based on extensive research from the information publicly available to us and consumers at the time of first publishing the post. Information is based on our personal opinion and whilst we endeavour to ensure information is up-to-date, manufacturers do from time to time change their products and future research may disagree with our findings. If you feel any of the information is inaccurate, please contact us and we will review the information provided.

Have Your Say

2 comments on 'Does Ketosis Really Work For Weight Loss?'

  1. BTW I forgot to add citations, which should always come from credible sources. I did not need to be selective in finding these. A quick search on PubMed (peer-reviewed scientific articles) for “ketogenic diet” immediately returns a list of positive outcomes, and nothing in line with this article. Many are related to epilepsy, but still relevant – ketogenic diets have been used for many years in epilepsy treatment. Long-term studies of general health side effects, such as cardiovascular health and longevity, exist and should be of relevance in other populations. I will admit that for many of these I have not read the full text that is behind a paywall so technically could mention other things, but the abstracts all contain the background, approach and general findings. – “Ketogenic diet modifies the risk factors of heart disease in obese patients.” – “Long-term effects of a ketogenic diet in obese patients” – “Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets.” – “Impact of the modified Atkins diet on cardiovascular health in adults with epilepsy.” – “A ketogenic diet supplemented with medium-chain triglycerides enhances the anti-tumor and anti-angiogenic efficacy of chemotherapy on neuroblastoma xenografts in a CD1-nu mouse model.” – “10 patients, 10 years – Long term follow-up of cardiovascular risk factors in Glut1 deficiency treated with ketogenic diet therapies: A prospective, multicenter case series.” – “Rationale, Feasibility and Acceptability of Ketogenic Diet for Cancer Treatment.”

  2. I appreciate the attempts at impartial review on the site, but this one looks more like reciting things that you have heard than actual research. “Ketosis is thought to cause…” – thought by whom? This is pretty vague. I have followed a ketogenic/low-carb approach for a long time (it is not new, or even newly popular), and although there are pros and cons, have never seen any of this reported by a credible scientific study of the diet. What are reported include weight loss, normal blood sugar, normal metabolism, improved cardiovascular health, reduced reliance on insulin for diabetics, improved memory and reduced cancer risk. There are some potential counter-arguments but none of the ones on the list I started to quote earlier. Fiber is also permitted on the diet in unlimited quantities, so that digestive statement here is inaccurate, as is the baseless piece about it completely destroying normal metabolism. Most often cited are tiredness while transitioning into the diet, social difficulty in staying on it, and potential nutrient deficiencies if people do not approach the latter with care.

    Ketogenic diets are used successfully by a number of endurance athletes, but there can be performance changes in the gym as you mentioned for some, especially in the beginning or in sports that require fast access to energy bursts. Not much noteworthy for the average less-than-serious athlete.

    BTW, for most practitioners of the approach (not necessarily the odd, Tim Ferriss-sponsored variant with the “bulletproof coffee” and expensive supplements) “keto” is basically the Atkins diet, which did in fact recommend staying at or on the edge of ketosis as a long-term lifestyle. The key difference among the more “extreme” variants is highlighting an idea already noted by Atkins that is often overlooked – for some people, too much protein can reduce the efficacy of low-carb eating because your body can convert protein to glucose. “Atkins” should also not be confused with the franken-foods marketed by his company since his death. I suggest this review should support any opinions with research on all sides, rather than “it is thought…”


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