Science

Sorry NY Times: The Key to Weight Loss is Still Quantity, not Quality

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Transcript:

An article in the New York Times announced that a new study shows “The Key to Weight Loss Is Diet Quality, Not Quantity,” which caught my eye because scientifically speaking, the quantity of your diet is absolutely the primary driver behind your weight. It’s an indisputable scientific fact that if you burn 1500 calories a day but you eat 2000 calories worth of bananas every day, you will gain weight. If you eat 1000 calories of Twinkies every day, you will lose weight. It’s ultimately about quantity, not “quality.”

Reading the article, as usual, debunks the headline. In case other people are confused, I wanted to make a video laying out exactly what is right and what is wrong about the headline, the article, and the study behind it.

The study itself did not test “quantity” versus “quality” in diets, and so it should absolutely not be used to support one over the other. If it were comparing those two factors, you could imagine it would involve two groups of people (at least): one that ate “high-quality” food (nutritious, home-cooked, or whatever other trait you consider high-quality) in whatever amount they wished, and one that ate whatever food they wished in low-quantity (fewer calories than they burn on a daily basis). In fact, this study compared two groups of people, all of whom ate “high-quality” food and none of whom counted calories in their food. On average, both groups lost some weight, but we have no way of knowing if they lost more or less weight compared to people who learned to count calories.

The actual difference between the two groups was that one group ate low-fat foods and the other ate low-carb foods. The actual purpose of the study was to determine if people’s genetics or insulin levels impacted how much weight they lost on these diets, as people like Gary Taubes have made millions telling the world. The study results contradicted Taubes’s assertions: neither insulin levels nor genotype predicted how much weight subjects lost. In other words, sorry, but a calorie is a calorie.

That should have been the headline but instead they went with this idea that can almost be interpreted to contradict those findings: calories don’t matter and it’s all about what foods you choose to eat, despite the fact that the study found that the actual foods you eat don’t matter. In a perfect world, that wouldn’t be the takeaway here, though it could be the impetus for another study to follow-up on this one. When you conduct a study and you find something strange that you weren’t looking for, you don’t generally publicize that as your finding — you set up a new study, with a new hypothesis, to further investigate that strange thing and verify that it’s not a statistical blip.

Until we get another study, I will say that it IS interesting that people, on average, lost weight on this diet in which they weren’t actively counting calories. The diet involved teaching subjects how to choose more nutritious foods while avoiding heavily processed food that contains a lot of sugar, and how to pick whole wheat over white bread or brown rice over white rice.

Does the fact that they lost weight mean that calories don’t matter? No, just the opposite — in fact, the study found that the subjects ended up consuming fewer calories than they previously had, which is why they lost weight. So really, this is not a problem of physics as much as it is one of psychology — the study may suggest that people can be tricked into consuming fewer calories by teaching them to eat more nutritious foods. And this makes sense, considering that it’s really, really difficult to eat 2,000 calories of spinach and it’s really, really easy to eat 2,000 calories of ice cream. When you avoid “junk” food, you’re more likely to eat fewer calories by accident.

Here’s why that’s an important distinction, compare to the headline: we have no idea how sustainable that is. If people don’t understand why they’re losing weight, they risk gaining it back if they find a “whole” food they love that is a calorie bomb (like avocados, for instance) and overeating again. Or, they may get fed up with never having “treats” and give up their new lifestyle entirely. One of the nice things about calorie counting is that I know I can have an ice cream sundae if I eat fewer calories for dinner and add a run into my day. One of the reasons many people give up on “diets” is because they miss eating the things that used to bring them joy.

So to sum up, it’s an interesting study that disproved its hypothesis, which had nothing to do with calorie counting. And it’s a misleading headline in the New York Times that is only partially redeemed in the article. But hey, I bet Gary Taubes is relieved that they made the story about calorie counting instead of the actual result of the study, which debunked his life’s work.

Rebecca Watson

Rebecca leads a team of skeptical female activists at Skepchick.org. She travels around the world delivering entertaining talks on science, atheism, feminism, and skepticism. There is currently an asteroid orbiting the sun with her name on it. You can follow her every fascinating move on Twitter or on Google+.

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6 Comments

  1. You know, the point about the title being out of whack with the article has come up in these pages many times before.

    The point I want to make is, that title may not be the author’s fault, at least not entirely.

    Several times in my life, something I have written has had the title changed by somebody else, be it a coauthor, a professor or somebody who I have trusted and ought to know better – in this case, perhaps an editor.

    I had gone along with it at the time and lived to cop the fallout because the article was NOT written to that title and the context had changed.

    For instance what had been a secondary point now becomes the main point and there may not be enough data to support that conclusively – or something along those lines, let’s keep it vague.

    The point being, I feel sorry for the author in that scenario because I have been there and done that and I bet it happens all the time.

    For this reason if I were to write an article these days I would always insist on my own original title.

  2. That being said, New York Times shits me to tears sometimes.

    A couple of weeks ago they had an article up with the title
    “Wall Street Falls…” with quite a dismal, negative and almost hysterical story.

    There was even a live chart attached – showing not a decrease but a 0.4% increase!

    Turns out there was a fall of just 0.3% 15 minutes before, which must have triggered the article.

    Wall Street was in fact up on that day and on following days.

    Said article has now been removed but it was up long enough to cause confusion and panic if you failed to read the actual data and make your own conclusions.

    All this made me think back fondly to Bad Chart Thursdays.

  3. I’m afraid that I have to disagree with what seems to be the skeptical ‘party line’ on weight loss, which is that all it is about is ‘calories in vs calories out’. My issue with that equation is that it’s a restatement of the problem, not a solution. Telling a person with a weight/eating problem that they need to burn more calories than they ingest is the same as telling somebody with depression that the solution to it would be to be, on average, happy more often than they’re sad, or that the solution to poverty is that poor families should earn more money than they spend. In other words, it’s strictly true, but not at all helpful.

    In a society like those within the current western world, where a majority of people have control over the food that they buy and eat, as opposed to places where there are food shortages or terrible poverty, the question of psychology, which you just gloss over as a minor factor, is in fact the most important factor that is contributing to obesity. There seems to be a type of magical thinking involved within the skeptical/scientific world, whereby we say “people just have to eat less and exercise more”, ignoring the evidence that these are not things that people are doing. In fact, it seems that as our cultures knowledge of nutrition, health and lifestyle improves, obesity is becoming more of a problem. This is definitely a correlation without a cause necessarily being present, but it at least disproves the idea that all that’s needed is education.

    For what it’s worth, I don’t like any of the ‘fad diet’ people or the Taubes of this world who come up with simple solutions and sell books with them before they’re proven. But I really don’t think that physics is the right way to look at what is a cultural and psychological problem.

  4. >It’s an indisputable scientific fact that if you burn 1500 calories a day but you eat 2000 calories worth of bananas every day, you will gain weight. If you eat 1000 calories of Twinkies every day, you will lose weight. It’s ultimately about quantity, not “quality.”

    But it isn’t. It is’t ‘ultimately about quantity not quality’. AT.ALL. Yes, if you put the bananas and twinkies in calorimeter and measure energy output, 2000 calories of bananas will release twice as much energy as 1000 calories of twinkies. Great, we’ve performed a simple Grade 10 Science experiment but any time you think you solved a major societal problem by performing a Grade 10 Science experiment you’re probably on the wrong track. What does that experiment tell you about humans and diet and anything interesting about those? Nothing. In fact, less than nothing because it puts you on the wrong track to think about the problem of obesity.

    Certain calories mess with your body and metabolism in profound ways. They mess with your hormones, and induce measurable psychological effects**. You may get depressed, irritable, hungry more frequently. Your judgment may get impaired. You may get addicted like a drug addict to the high you get from eating and crash and eat again. Foods may exacerbate or suppress existing pathologies. Your body handles different calories in different ways. The way the calories are carried into your body makes all the difference. For example orange juice is way worse for you than raw oranges – because the sugar in Oranges is locked in with a ton of fiber. It’s trivial for humans to ingest a mass amount of calories by drinking juice. It’s physically hard for humans to ingest the same amount of calories by eating raw oranges.

    **It’s actually really scary how much diet affects your psychology. For example, one widely passed around study showed disparity in parole grants by judges based on whether or not they were hungry at the moment.

    1. Your point is good, that it’s a lot EASIER to restrict calorie intake with a high fibre diet. Calorie restriction is still necessary though.

      In actual fact I have done something similar to Rebecca’s Twinkie diet, though not for weight loss but to try and heal after a botched surgical procedure.

      The diet was 100% carbohydrate, 2 liters of lemonade per day for two weeks (125 ml/hour, on the hour, 800 calories/day). I lost 4-5 kg; strangely I was not affected by hunger at all, though I did have a powerful incentive.

      So with discipline, an all carb diet can work for a short period, but highly not recommended, do not try this at home kids!

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