Health tips you shouldn’t believe in: carbohydrate restricted diet

Health and Diet

On TV and in magazines, new health methods are born and disappear every day.
The contents range from the obviously dubious to those that have the stamp of approval of active doctors.
If you see a doctor recommending it, you may be tempted to try it.

However, no matter how expert the opinion may be, it should not be casually believed.
The only way to move in the right direction is to steadily check each piece of data based on the scientifically determined reliability of the study.

Therefore, we will focus on health practices that are often recommended by professional doctors on TV and in magazines, and which are “actually baseless” or “dangerous” to the body.
In this article, I would like to introduce the results of a study on “carbohydrate-restricted diets” in particular.

Is sugar restriction the most powerful health method?

The “carbohydrate-restricted diet” has now become a standard health and diet method.
“Many people claim that carbohydrate restriction is the best diet, and some doctors say that it improves mood, is effective in treating cancer, and gives you more energy.

Indeed, it is very easy to lose weight in a healthy way by simply cutting out carbohydrates and reducing hunger.
In recent years, carbohydrate-restricted diets have been adopted by diet services with great success.

With so much support and results, it seems safe to say that carbohydrate restriction is the most powerful health and diet method.
To what extent is a carbohydrate-restricted diet a scientifically accepted method?

The weight loss effects of a carbohydrate-restricted diet are the same as the effects of other dieting methods.

Let's start by looking at the weight loss benefits of a carbohydrate-restricted diet.
The most reliable study at the moment is a large paper published by the University of Toronto in 2014.
This is based on an analysis of 7286 high-quality data from a large number of previous diet studies.
Johnston BC, et al. (2014)Comparison of weight loss among named diet programs in overweight and obese adults: a meta-analysis.

A total of 11 different diets were compared, including carbohydrate-restricted, low-fat, calorie-restricted, and high-protein diets.
From the many diets available, you have chosen the one that will help you lose the most weight.
The results were as follows.
After 12 months of dieting, you will lose the same amount of weight no matter which diet you use. There is no difference in dieting methods.
No matter what diet you use, you will lose the same amount of weight in a year.
Some people who support a carbohydrate-restricted diet say that they don't need to worry about calories.

When I say this, I sometimes get objections like, “Super carbohydrate restriction should make a big difference.
“Super carbohydrate restriction” is a method of reducing the amount of carbohydrates even more than a typical carbohydrate-restricted diet, usually aiming for less than 10% of total daily calories.
However, many experiments have shown that even a super carbohydrate-restricted diet does not produce remarkable results.
For example, in an experiment conducted by an Australian government agency in 2006, middle-aged people in their 50s were divided into two groups: those who ate a diet containing 4% sugar and those who ate a diet containing 40% sugar.
The calories in the diet were aligned to 1500 kcal per day, and we checked to see what difference 8 weeks would make.
Noakes M, et al. (2006)Comparison of isocaloric very low carbohydrate/high saturated fat and high carbohydrate/low saturated fat diets on body composition and cardiovascular risk.

A 4% sugar content is a level of restriction where you can't eat rice or bread completely, and can eat almost only green and yellow vegetables.
This is a very hard super carbohydrate restriction.

However, after 8 weeks, I did not notice any difference.
Whether I cut down on carbohydrates to the bare minimum or ate regular carbohydrates, my body fat was reduced in the same way in both cases.

In other words, what's really important in dieting is to stick to the first method you choose, and not to look for different methods.
There is no need to force yourself to choose a carbohydrate-restricted diet if you like white rice and bread.

Why does carbohydrate restriction seem to work?

Some of you may have the following questions here.
I've seen data in books and on TV that says carbohydrate restriction is effective for weight loss, but is that not correct?

The reason for this discrepancy is that most experiments on carbohydrate-restricted diets do not take calories into account.
For example, let's say you want to compare the effects of “carbohydrate restriction” and “low-fat diet” for person A and person B.
Of course, in a real experiment, we would have many more participants, but for the sake of simplicity, we will focus on a diet for two people.
At this point, in most experiments, the following instructions are given to two people.

  • Instructions to Ms. A: Reduce sugar and let her eat as much as she wants.
  • Instructions to Mr. B: Reduce fat and have him eat as much as he wants.

You just cut back on either sugar or fat, and the rest of the time, you let people eat until they are full, without worrying about their daily calories.
Interestingly, when experiments are conducted in this way, it is often the case that the carbohydrate restriction is more likely to result in weight loss.
Dr Deirdre K Tobias, et al. (2015) Effect of low-fat diet interventions versus other diet interventions on long-term weight change in adults: a systematic review and meta-analysis
There are many theories as to why this is the case, but two of the most popular are as follows.

  1. Reducing carbohydrates naturally reduces calorie intake because you are limited in what you eat.
  2. The reduction in carbohydrates increases the amount of protein, which suppresses appetite.

The first theory needs no detailed explanation.
If you want to reduce sugar, you have to cut down on staple foods such as rice and bread, which will naturally reduce your total calorie intake.

You don't lose weight because you reduce sugar, but because you indirectly reduce calories.

After all, you're indirectly losing calories.

Another popular idea is that this is due to an increase in the intake of protein sources such as eggs and meat, instead of a decrease in carbohydrates.
This is because many studies have shown that increasing the amount of protein in your diet can temporarily reduce your appetite.

David S Weigle, et al. (2005) A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations

Both theories have different mechanisms, but the final conclusion remains the same.
Reducing sugar in itself does not have a magical weight loss effect, but it indirectly reduces calories, which is why you lose weight.

However, as the study mentioned above shows, no matter what diet you follow, the results will not change after a year.
A high quality paper published by Stellenbosch University in South Africa in 2014, after reviewing data from about 3,000 people, concluded that
The study followed obese adults for two years and found no difference in weight loss or incidence of heart disease between a carbohydrate-restricted diet and a balanced diet (a diet with a high percentage of carbohydrates) when the daily caloric intake was kept the same.
Celeste E. Naude, et al. (2014)Low Carbohydrate versus Isoenergetic Balanced Diets for Reducing Weight and Cardiovascular Risk: A Systematic Review and Meta-Analysis

Again, if you keep your daily calorie intake the same, whether you eat less carbohydrates or more carbohydrates, you will see no difference in your weight change.
The more calories you reduce, the more weight you will lose, both in the same way.

In short, the key to dieting is to reduce total calories in a way that is as easy on you as possible.
Whether it is carbohydrates or fats, if you reduce the amount of carbohydrates in your diet by 100~150 kcal each meal, your body fat will naturally decrease.

Is a carbohydrate restricted diet really safe?

Next, let's consider claims such as “reducing sugar will make you healthier”.
Currently, the world of carbohydrate-restricted diets is divided into two camps: proponents and detractors.
Proponents claim that carbohydrate restriction can prevent various diseases, while opponents say that carbohydrate is an important nutrient and long-term practice is dangerous.

Unfortunately, the results are unfavorable to a carbohydrate-restricted diet at this time.
One of the most famous is a paper published by the International Medical Research Center in Japan in 2013.
Noto H, et al. (2013)Low-carbohydrate diets and all-cause mortality: a systematic review and meta-analysis of observational studies.
The research team selected 17 studies from the past database.
The data from about 270,000 people was carefully examined to determine the relationship between a carbohydrate-restricted diet and mortality.
Although there is no comparison of calorie intake, it is the most reliable conclusion at this time.

The results were unequivocal: “A carbohydrate-restricted diet increases the overall mortality rate by about 1.3 times.
What's more, if you stay on a carbohydrate-restricted diet for more than five years, the mortality rate is likely to increase.
After all, we should consider carbohydrates as an indispensable nutrition for humans.

Incidentally, immediately after this study was published, there were many objections from supporters of carbohydrate restriction.
For example, one doctor wrote on his blog, “The papers (concluding that carbohydrate restriction increases mortality) are a cobble together of selected references.
In short, this paper is bad because it contains poor quality data.

However, this opinion is a tyranny that twists the way we look at data.
Of course, it is better to use only high quality research, but there is always a limit to the accuracy of the experiment, so there will always be some low quality data mixed in.

For this reason, when we compile a large number of papers and draw conclusions, we rank the quality of each study and give more weight to the higher quality data.
Even so, there will be errors, but the overall conclusion will be towards the right direction.

I don't know how much this doctor believes his own counter-argument, but in any case, a long-term carbohydrate-restricted diet is not recommended at this time.
Even if you do want to try it, it is best to limit it to a few months.

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