Dr Aidin Rawshani

Low-carbohydrate diet (LCHF) and ketogenic diet (strict LCHF) interest scientists


Increased interest in the low-carbohydrate diet (LCHF) and a ketogenic diet (strict LCHF) among scientists

David Ludwig is a professor at Harvard University. He has received approximately SEK 100 million in research grants to study low-carbohydrate diets (LCHF, ketogenic diet). Professor Ludwig says the following:

We know that most chronic diseases in the country depend on lifestyle, especially dietary habits. It should be our top priority to invest in qualitative, long-term, rigorous research, so that we can answer questions about low-carbohydrate and low-fat diets, which has confused us for a century”

In recent years, more and more scientists have been interested in how low-carbohydrate diets (LCHF) and ketogenic diets (strict LCHF) affect overweight, obesity, diabetes, blood lipids, blood pressure and other risk factors for disease and death. The big question has been which of the following is best:

  • Low-carbohydrate diet – Eating fewer carbohydrates.
  • Low-fat diet – Measuring less fat.
  • Low-calorie diet – Eating less food (fewer calories.

What we eat is undeniably important for our health and well-being. Therefore, this issue is of importance to every human being. Although the issue seems to be more relevant to a person with overweight, obesity or diabetes, it should actually also interest healthy people and normal weight individuals.

Low-carbohydrate diets, low-fat diets and low-calorie diets contradict each other. Proponents of the low-carbohydrate diet argue that carbohydrates are the cause of excess weight, obesity and diabetes. Proponents of the low-fat diet argue that fatty foods (the food content of fat) are vital for weight. Both low-carbohydrate and low-fat diets can be maintained over longer periods of time. One can thus establish one of these diets as “their everyday” diet and maintain it for a long time. Caloric low (low-calorie) diet, on the other hand, is very difficult to maintain over long periods of time and that type of diet should be seen primarily as a temporary method of losing weight.

We have already written detailed reviews of the following topics:

  • The science behind LCHF, where we noted that there is strong scientific support for the low-carbohydrate diet.
  • How to lose weight with the change of diet.
  • Low-fat food
  • Low-calorie diet

LCHF and the ketogenic diet is becoming more popular

In recent years, interest in low-carbohydrate diets (LCHF) and ketogenic diets has increased. It is mainly popular blogs, media and private individuals that have driven the interest. The researchers were initially more skeptical, but more and more have been interested in LCHF. A wide range of publications in some of the world’s most prestigious medical journals has testified that LCHF is effective and safe.

The fact that LCHF has previously met with skepticism from scientists and doctors is not so difficult to understand: in all books on biochemistry and physiology, it is reported that the human body prefers carbohydrates as an energy source, and that fat is used only as a secondary source of energy. It is true to a certain extent: if the body receives both carbohydrates and fats, then it will choose carbohydrates as fuel in the first place. However, this does not mean that the food that we eat today (a lot of carbohydrates) is more healthy than foods with a lot of fat and little carbohydrates. The two big questions are:

  • How many carbohydrates do we need?
  • Is it healthier to reshape the body, so that it burns fat instead of carbohydrates? This requires to properly limit carbohydrate intake, and thus eat LCHF.

Now more and more scientists are interested in LCHF and the ketogenic diet. 8 For scientists, the big question is whether a ketogenic diet has metabolic advantages over other slimming methods. We know that the difficult thing is not only to lose weight but also to maintain their weight loss. Basically every study that followed participants over a long time shows that participants are gaining weight again. Here are diagrams from a large study where you can clearly see that weight loss with different diets is successful at the beginning, but after that, the participants gain weight again.

Why are we gaining weight again?

The explanation seems to be simple: after a heavy weight loss, the body’s metabolism and hormonal balance changes, so that you get hungry, you get reduced sleep burning and the body’s ability to make fat improves. This means that people who lose a lot of weight, unfortunately, get easier to gain weight! 9

Scientists are now wondering whether LCHF and the ketogenic diet are better in this regard. That is: is ketogenic diet better when it comes to hunger, metabolism and fat storage? In a large analysis, which included 13 clinical trials, people who ate a ketogenic diet were losing more weight and maintained more of their weight loss than those who ate low-fat foods. 10

There is also evidence that a ketogenic diet affects metabolism better than other diets. Of particular interest is the body’s resting burning, which is the burning the body maintains at rest. Since we are at rest more of the day, rest combustion is important for our total combustion. It is known that any type of weight loss (resulting from dietary changes) leads to reduced rest burning.

The body simply reduces metabolism when losing weight. There are studies that show that the reduction of rest burning is the least with a ketogenic diet. If that is correct, the ketogenic diet has a great advantage, as you want high rest burning. 11

What does a metabolic benefit entail to me?

If it is true that LCHF and the ketogenic diet have benefits in terms of metabolism and hunger, then the number of calories you eat is not as interesting as the origin of calories. Then begin to speak about the “quality” of calories. The point is that calories coming from fat are better for metabolism, compared to calories coming from carbohydrates.

There is no doubt that research in this area is needed. Scientists, doctors, authorities and international organizations have been recommending low-fat food for decades. In the same period, the incidence of excess weight, obesity and diabetes has exploded all over the world. Up to half a million Swedes have diabetes or precursors of diabetes (type 2 diabetes). It is only in the last 20 years that scientists have begun to understand that sugar and carbohydrates can be one of the main reasons for this.

The usual Swedish diet contains 55-65% carbohydrates, which can give up to 400 g of carbohydrates per day (depending on the total caloric intake). The number of grams of carbohydrates, and especially the quality of carbohydrates we eat, seems to be both unnatural and unhealthy. With a ketogenic diet (LCHF), carbohydrate intake is sharply reduced. LCHF means that you definitely eat 100 g of carbohydrates per day (preferably 70 g) and a ketogenic diet involves eating 20-50 g of carbohydrates per day.

For LCHF, the quality of carbohydrates is also important: sugar and starch should be avoided. The purpose of this is to avoid sharp increases in blood sugar and reduce the total release of insulin into the body. The reason is that insulin drives the development of obesity (insulin leads to fat being stored, and the breakdown of fat decreases).

What is ketosis?

Ketos is a condition where the body switched to breaking down fat to use it as fuel. Fat is broken down into fatty acids that are converted to ketones (ketone bodies) in the liver. The ketones, in turn, can be used as fuel in the body.

In other words: restriction of carbohydrates leads to the breakdown of fats → release of fatty acids → production of ketones → high levels of ketones in the blood. This condition is called “ketosis”. The important thing is that ketones can also be used by the brain, contrary to what many believe. The rest of the body can also use ketones as fuel.

How proteins affect ketosis

Proteins are satiating and there appear to be no serious consequences of eating a lot of protein (see Masterpiece PURE). However, for those who want to lose weight with the help of ketogenic diet, proteins can pose a problem. Proteins can be converted into sugar (glucose) and then the blood sugar rises, which leads to the release of insulin, thereby interrupting the breakdown of fats. (The fact is that protein itself also stimulates the release of insulin). Therefore, those who wish to lose weight with a ketogenic diet should balance the protein intake to (1) avoid excessive intake but (2) still eat enough protein to preserve their muscle mass and other organs.

To eat until you get full

Proponents of ketogenic diet often point out that the ketogenic diet and LCHF allow eating until saturation, which is slightly sensational because competing diets usually advocate limiting food intake. This clearly facilitates the first time with the ketogenic diet and LCHF, as you lose weight quickly in the first time without having to be hungry. It should be mentioned that some of the weight loss in the first 10 days is due to the loss of fluid, which is explained by the fact that the ketogenic diet makes you urinate more. However, the subsequent weight loss is due to fat breaking down as insulin levels in the blood decrease.

As we discussed earlier, the ketogenic diet and LCHF actually lead to a reduction in food intake, without being instructed to do so. This is explained by the fact that one is not as hungry. 12

Research on the ketogenic diet is becoming more and more convincing. A new study shows that after 8 weeks of the ketogenic diet, the body’s fat mass was reduced by 9.7%, compared with 2.1% on low-fat diets. In addition, visceral fat (fat around the organs of the abdomen, which is considered the main cause of diabetes) decreased 3 times more with a ketogenic diet. 13

Diabetes and LCHF/ketogenic diet

One of the biggest surprises with LCHF and the ketogenic diet is the effect on type 2 diabetes. We have already discussed studies, which actually show that LCHF has a good effect on blood sugar, long-term blood sugar (HbA1c), blood lipids, blood pressure and weight loss among people with type 2 diabetes. This is surprising because the ketogenic diet leads to getting more fatty acids and ketones into the blood and many researchers believe that high levels of fatty acids in the blood are part of the cause of type 2 diabetes.

As discussed earlier, up to 95% of diabetics who eat LCHF/ ketogenic diet can either reduce or completely stop their antidiabetic medicines. See chapter Science behind LCHF and the ketogenic diet.

Long clinical experience with a ketogenic diet can be found in several hospitals. Dr. Eric Westman (Duke University) has long used ketogenic diet as an alternative to obesity surgery (bariatric surgery) and drug therapy. Dr. Westman and other doctors are beginning to see the ketogenic diet as a long-term alternative that is particularly suitable for people with diabetes and metabolic syndrome. According to Dr. Westman’s experience, patients manage to shift their diet to ketogenic diet/LCHF. 14

Is ketogenic diet and LCHF safe/harmless?

The ketogenic diet has been used for almost 100 years in various contexts, especially to treat epilepsy. Ketogenic diet and LCHF are considered safe. However, there are side effects with LCHF/ketogenic diet, which we discussed earlier. People with diabetes should discuss dietary changes with their doctor as medication doses may need to be adjusted (reduced).

Do you have to limit carbohydrates for life?

Yes, sir. With a ketogenic diet/LCHF you can — if you want and dare — start eating a little more carbohydrates once you have reached your target weight. For the vast majority, you can maintain your weight loss even if you start eating a little more carbs. However, it is important to find a level that will prevent you from gaining weight again. If you have diabetes, you should be extra careful and consider the long-term restriction of carbohydrates (after all, it has a very good effect on diabetes).

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