All you need to know about weight loss and dietary studies.
Think about what happened last Monday as a cautionary tale about how to read the literature and reports on studies. In the morning, the news sites published a story about the reinvestigation of Annals of Internal Medicine, showed that a low carb diet was the way to be thin in the future. By the time the evening news started coming out, there were a JAMA study that contradicted the findings of the study in the morning, showing that all diets - low fat or carbohydrate - work the same way, regardless of the compositions macronutrient.
If your head was spinning when you went to bed, you were not alone. There is a lot of research on weight loss. And there's good reason why the various studies reach different conclusions, which we will review in detail below.
All you need to know about weight loss
But first - and I write it at first, because I do not want to miss it - if you want to extract only one thing from this article on what works to lose weight, here it is: there is no magic diet or steamroller stomach, nor wonders for weight loss or diet food. You can ignore the noise, fashion, branding, diet books promoted by celebrities, and miracles to increase metabolism Dr. Oz. You can even ignore the conflicting studies that come out every few months, or in this case, on the same day.
All you need to know about dieting is fairly straightforward. What works is to reduce calories in a way that you like and you can keep. Less calories means more weight loss. It's very simple. You can stop reading if you want.
Why diet studies reach different conclusions?
If you like the details, then keep reading. Probably you're curious about these two studies, what they mean in the context of all the other literature on diets, and why have contradictory conclusions.
I'll explain. The first study-which supported the low-carbohydrate diet for weight-loss was performed in 148 obese men and women, black and white, which half were randomly assigned to a diet low in fat and the other half a diet low in carbohydrates. Participants were followed for one year, and in the end, researchers found that the low-carb group lost 6 kilos while the low-fat group lost 2 kilos.
But although it seems that the low carb diet gained like everything dietas- studies it had great limitations.
Dr. Yoni Freedhoff, a doctor of obesity based in Ottawa and author of "Diet Fix", he realized that the circumstances of the study did not reflect the real world. A study participants were replaced one meal a day (a shake or a bar) and received regular help with your diet. "That changes the results of the study, when people go on a diet with amazing a bench and a partial meal replacement," he said.
Furthermore, the study only lasted a year, and the general consensus in the scientific community is that you need at least two to see if weight loss is real and if maintained over time.
Still, Dr. Freedhoff said he was not surprised that the low-carb group lost more weight. "Other studies of people with low carb diets show that they consume fewer calories than people without such a diet.It's true! But is thought to be a consequence not only of the reduction of carbohydrates, but the increase in protein and distribution of this protein throughout the day. "The protein is more satiating than other macronutrients, so people generally eat less if proteins replace carbohydrates.
Again, however, for studies of protein are also short-term. The long-term studies show that people can not follow low carb diets. Even in the investigation of Annals, in Figure 2 can see that the amount of carbohydrates that participants was eating increased during the year. "In two or three years," Freedhoff said, "I suspect that both groups are going to look like."
The rigor of these two diets is also different: the low-fat group had to lower fat intake on a 1/7, while the low-carb group had to stop eating 5/6 of your carbohydrates. "My view on this is that part of the difference in weight loss between the two groups is explained by this difference," said Christopher Gardner, a professor of the Prevention Research Center at Stanford, which studies the diet. "People who lost more had to pay more attention to leave those carbs."
So it was not necessarily the content of their diets, but that had to be very careful about what they put in their bodies even more than the low group in fat- what caused this group to lose some extra kilos.
What about the other new study showed that all diets have the same effect?
The JAMA study released Monday was different Lover low carbohydrate diet for one simple reason: it was a meta-analysis, meaning that the authors pooled the results of 50 trials including 7,300 people to see which diet program -from the Atkins until Ornish- worked better. These meta studies are generally considered the gold standard of evidence, because they reduce the fairness in individual studies to look at the evidence on any research question in its entirety.
THE AUTHORS OF THE STUDY CONCLUDED THAT THE BEST DIET IS THAT A PERSON WHICH MAY BE FOLLOWED BY LONG TIME.
Overall, the researchers found that the macronutrient content of a diet does not matter. After six months, those on low carbohydrate diets lose about 9 kilos, while those on low-fat diets lose 8 kilos. After 12 months, each group has regained a few kilos and the difference between the two groups disappears.
The study authors concluded that the best diet is one in which people can continue for long. And that is a conclusion echoed a large scale, by comparing the results of different weight loss programs.
Why is the study of the diet is almost as difficult as losing weight?
Studying the diet is difficult. If you put people in a laboratory and measure it carefully everything they eat, get an accurate picture of what went into their bodies, but the results will not reflect what happens in the real world. If you release the participants and ask them to report back caloric intake with little monitoring, you get an inaccurate view, because people are notoriously bad to remember what they ate and often think they consumed fewer calories.
Studying the diet is also very expensive. So the studies tend to be short term, and do not reflect the results that would in the real world. And we know that most people, sadly, gain weight again after a while. So to understand if a diet works or not, a study that lasts for more than a year ... and those are much more expensive and difficult to finance needed.
Culture also matters. This classic study comparing weight loss low carb diets low fat diets found that the low-fat group was less successful than the other. The study was conducted in Israel, Dr. Frank Sacks of Harvard told Vox, "In Israel, for starters, people have a Mediterranean-style diet, so I think that the customs of the people-what they like trade has a lot to do with the success of a particular diet. "
Conclusion: What diet really work?
Well, I told them from the beginning. But if you have read this far, I will reward you with an easy way to cut calories: eat less at restaurants and stop drinking sweetened beverage. We also know that people who have their calorie intake and weighed regularly lose more weight than people who do not.
Dr. Freedhoff - who has worked with thousands of obese patients and on weight- says, "at the end, you need to enjoy your life when it comes to food, if they want to stay in time. It's crazy to think, with billions of people on the planet, there is only one approach fits all "He adds:".. The best diet for an individual is the worst diet for another "
Tim Caulfield, author of the book "The Cure for All" also answers this question excellently: "Be aware of all the forces that exist in our culture (and in us) who are constantly trying to push us away from a pattern of healthy food. These forces include our own misconceptions about us and what we eat ... Rejects fast food. Do not be fooled to accept larger portions, you do not press your friends, work situations or to avoid travel to eat healthy. And do not be fooled by labels that say "healthy" and "organic" on packaged food. Since they are mostly marketing tools .... Simplicity is the revelation. "
Ever more like once a study on diets?
Even diet gurus are sick. Dr. Sacks said he is hopeless about all these "fads that come and go" with different diets popping fashion every few years. Stanford Gardner also said that these studies focus on the "best diet" are mostly a waste of time, because usually they are of poor quality and do not provide much information anyway.
"It's the wrong question," he added. "A better question would be" What is the best diet for different individuals, and how can we bring them together? "To understand this, Gardner said researchers need to see the genetic makeup of people, and how they respond to a particular diet. Until science reveals this in a more refined way, remember Caulfield: simplicity is revelation.
