The Pundit was reading his copy of Time magazine and was intrigued by an article, titled, “Why Exercise Won’t Make You Thin.” First, as one who has struggled with his weight, this looked like a great article because it would give me an excuse not to exercise. Second, as a produce professional, it seemed like if exercise wasn’t the solution, diet must be, and that could rebound well to the interests of the produce trade.
So we dove in. We didn’t much like the article… it was a weird mix of personal anecdote and snippets of interviews and studies without much quantification. We perked up, though, when it referred to Dr. Timothy Church and his research.
Tim is the son of Tom Church, and Tom has often contributed to the Pundit including a letter we incorporated into this piece:
We also dealt extensively with Tom when a food safety crisis threatened and then turned out to be based on a lab error; we called that piece, Church Brothers/True Leaf Recalls, Then ‘Unrecalls’ Spring Mix/Arugula After Testing Mishap.
We’ve also mentioned his son, Tim before in the Pundit as part of a piece titled, A Little Exercise Goes A Long Way To Better Health. That piece touted a book that Tim and his two co-authors wrote: Move Yourself: The Cooper Clinic Medical Director’s Guide to All the Healing Benefits of Exercise (Even a Little!).
Since that book was based on the premise that exercise was very valuable and even a little exercise helped a lot, it seemed odd to see Tim being quoted in this article with the opposite premise.
We wanted to understand what exactly was going on so we asked Pundit Investigator and Special Projects Editor Mira Slott to talk with Tim and find out more:
 |
Timothy Church M.D., M.P.H., Ph.D. Professor,holder of the John S. McIlhenny Endowed Chair in Health Wisdom Director of Preventive Medicine Research Pennington Biomedical Research Center Louisiana State University |
Q: We read with interest your comments and excerpted research in the counterintuitive Time magazine article: “Why Exercise Won’t Make You Thin.” Do the conclusions that physical exercise is counterproductive to weight loss and even may encourage weight gain jive with the body of evidence out there? What is your assessment?
The article seemed to pull your quotes out of context and make some unfounded leaps regarding your study. [Editor’s note: you can read the primary report on the effects of different doses of physical activity on cardio respiratory fitness published in the Journal of the American Medical Association here, and the more recent study on changes in weight, waist circumference and compensatory responses with different doses of exercise published in PLoS ONE here].
A: I wrote a letter toTime magazine to set the record straight. I told them I found the story to be full of gross inaccuracies and misleading statements, and the premise, as introduced in the title, entirely wrong.
Q: What were your particular grievances with the piece? Did you point out problematic areas in the analysis?
A: I specifically addressed the issue of compensation and physical exercise (PE) for kids. While we are convinced that caloric compensation exists and continues to be an active area of research for us, it is very important to point out that not everyone compensates in response to exercise training. In fact, the majority of people lose weight in response to exercise training even when no dietary advice is provided, as in our study that was described in the story.
Further, numerous research studies have shown that when individuals are directed to pay attention to what they eat, then exercise is an effective means to produce substantial weight loss. These studies are easy to find and have been conducted by the best weight loss researchers in the field, yet neither the studies nor any of the researchers are mentioned in the article.
The main point we try to make when addressing “compensation” is that regular exercise is not a license to eat anything you want, and that if you are interested in losing weight through exercise, make sure you don’t get in the habit of rewarding yourself with food.
Q: The Time article referenced a study by researchers at Peninsula Medical School in the U.K.; essentially that kids derived no discernable benefit from a bolstered PE program at school. Further, it highlighted another British study from the University of Exeter that found kids regularly moving in short bursts are just as healthy as kids who participate in sports with vigorous, sustained exercise. Is there validity to this?
A: I admonished this reporting in my letter. To use results from an Abstract (not a peer-reviewed paper) that are in direct disagreement with numerous research papers published from outstanding research studies, to support the unfounded premise that PE is not of value in children, takes journalistic irresponsibility to a new level.
Families, schools, and our country as a whole are struggling with how to combat the childhood obesity epidemic, and publishing statements suggesting that PE is of no importance in this battle is asinine. The evidence is overwhelming that PE is essential to the physical and mental health of our children, and it astounds me that someone could suggest PE is of no value.
Q: Looking at these issues in a broader context, what have you learned through your research about the complex relationship between diet and exercise for weight loss and health? How can the produce industry capitalize on this knowledge?
A: It’s an interesting time to have this conversation with healthcare reform consuming us right now. You’re hearing different discussions about weight and prevention. I get the feeling that nobody really knows what prevention means or has any real legitimate solutions other than it’s a cool word to say.
What you are seeing is people picking on the stuff that is easy to pick on — particularly, soft drinks or sugar. They’re talking about taxing high sugar beverages, which to me is kind of ridiculous because I just don’t think taxing is going to solve any issues. Rather than penalizing unhealthy behaviors, they need to be focusing on promoting healthy ones, for example, eating more fresh fruits and vegetables.
Nobody is really providing strong strategies for increasing fresh fruit and vegetable consumption in the U.S. I love how we subsidize all this sugar that is being produced but no one even thinks about subsidizing fresh fruits and vegetables, or increasing availability of fresh fruits and vegetables for people who don’t have access to them. This is an issue that is totally being ignored. A lot of people don’t have access to supermarkets and just shop neighborhood shops deficient in fresh produce.
It’s irritating to me, having grown up in a produce family, because I know there is no shortage of fresh fruits and vegetables, yet I’ll hear that complaint often. In fact, there is an excess. To me, there are these simple solutions that need to be considered at a national level. How can the government help get more fresh fruits and vegetables to people as opposed to getting unhealthy foods to people, which our government has had a long history being very good at.
Q: How does this relate back to what you’re studying?
A: Also tying into that is physical activity. People will talk about obesity, and they’re looking at tertiary issues like taxing soda as opposed to figuring out how we can build more parks and green spaces, and more bike paths. We live in this toxic environment where you can’t walk from point A to point B in the U.S. without taking your life in your hands because of traffic, and not having sidewalks. It’s kind of insane. That ties into what I do as an exercise researcher, and the study in particular that we’re talking about.
It was the largest exercise study ever conducted in women. It was a massive undertaking, with 460 women, specifically post menopausal, sedentary, over-weight with elevated blood pressure. So, individuals fairly high risk for cardiovascular disease. What we were looking at were different doses of exercise and the health benefits associated with it.
What was the minimum you could get away with? People were in the study for six months. All exercise was supervised. It was in our facility so we knew every step, every heart beat, every-everything. And we had this unbelievable exercise compliance. It was basically 100 percent. Very few women dropped out of the study.
We analyzed the effects of 70 minutes a week, compared to 135 minutes a week, compared to 190 minutes a week. Because it was such a huge undertaking — these studies have massive budgets, 30 or 40 staff involved, you want to get as much data out of this as possible. The primary paper was published in theJournal of American Medical Association quite a few years ago now, looking at fitness because how fit you are, how good a shape you’re in is a great predictor of whether or not bad things are going to happen to you from a health perspective. To our surprise, even the 70-minute-a-week group, or 10 minute a day group, saw improvements in fitness.
We subsequently have written a paper about exercise dose and quality of life. Once again, every single exercise group had an improvement in quality of life, even the 10 minute a day group. That was a finding that the press grabbed on to that as little as 10 minutes of exercise a day has benefits. Clearly the 150 minutes a week is the goal, but as little as 70 minutes a week has benefits. That’s really, really important.
Q: I’m hearing something different from you here than what was implied in the Time magazine article. Did you find exponential improvement for someone that worked out 190 minutes a week versus 70 minutes a week?
A: For fitness, no. It was actually almost perfectly linear. The more exercise you did the more you improved, but the idea that we saw any improvement in just 10 minutes a day to me is a very positive message.
Q: How do you define fitness and measure improvement? Do you have medical indicators?
A: When you talk about fitness, you should be losing 1 percent to 2 percent of your fitness, how in shape you are, per year. You get less fit as you get older; it’s kind of discouraging. We define fitness through a maximal exercise test. We put someone on a treadmill and we have them go as far as they can. So we’re measuring how thick their engine is. It is how much oxygen you can consume and utilize, or how much work you can do on the treadmill.
We hook people up to these fancy machines and we can basically figure out how big your engine is. And that’s what we saw. In the control group that did nothing, they lost about 1.5 percent of fitness. In the 70 minute-a-week group, they not only didn’t lose fitness, they actually had almost a 4 percent gain, so the net effect is about 6 percent.
Q: Aren’t there many factors in defining someone as more or less fit?
A: The way we do it, you put someone on a treadmill and they go to exhaustion, but fitness can be defined as how long they were on the treadmill after the exercise training. We’re actually measuring the gasses coming out of their mouth and nose. In medical terms, we can quantify how big your engine is.
Fitness is this abstract concept that’s hard to get your hands around. What we’re literally measuring is how good a shape you’re in. For example, before they might have tired out after two flights of stairs, and now they might tire out at six flights of stairs. We measure their ability to utilize oxygen on a treadmill. That really correlates well with how many stairs you can climb before you run out of gas.
Q: So could someone be overweight but more fit and in better shape than a thin person?
A: Absolutely. We talked about this for years how you have to pay attention to your weight, but you also have to pay attention to how physically active you are. The more physically active you are, the higher level your fitness. You can be fit but also overweight. We’ve shown fitness protects against the excess weight. Not everybody is going to be this mythical normal weight.
Q: Doesn’t this lead us back to the premise of the Time magazine article and the correlation between exercise and weight loss?
A: One of the papers we did was on weight. And this is where it got fun. Because all the exercise is supervised, we know exactly how many calories everybody burns. Because we know how many calories everybody burns, we know how much weight they should have lost. There are 3,500 calories in a pound. If you burn an extra 3,500 calories than you take in, you lose one pound. If you eat an extra 3,500 calories than you burn, then you gain one pound.
Q: It’s just calories, so it doesn’t matter if you’re consuming high-fat foods or low-fat foods in the process?
A: It doesn’t matter. It’s calories in, calories out. We were able to calculate this and what we learned was that the 70-minute-a-week group lost pretty much exactly what we expected them to lose in weight. The 135-minute-a-week group lost exactly what we expected in weight, but the group that did 190 minutes a week lost about half of what they should have.
There’s an important point here in that they lost weight. That was kind of missed in theTime article. But there were clearly some individuals there that didn’t lose as much weight as they should. This is an ongoing, active area of research for us.
What we suspect is not that people are hungry, but that they are rewarding themselves. Oh, man, I just did 70 minutes on a treadmill; I earned that jelly donut. Here’s where the problem comes in. People tend to greatly overestimate how many calories they’ve burned while exercising. They don’t appreciate that being on that treadmill for 45 minutes or an hour is only 300 or 400 calories.
In today’ calorically dense environment, you can easily nullify that with one muffin or a couple of glasses of wine. That’s the message we’re trying to get out there. If you’re concerned about weight, you have to focus on diet and exercise. You can’t just focus on diet and you can’t just focus on exercise.
Q: Some people, bypassing exercise completely, have great success losing weight, but most find it challenging to keep it off long-term. Every day, another diet food plan hits the market professing instant miracles. What is the most effective strategy to avoid yo-yo dieting?
A: One of the things that was completely missing from that article, which to me was insane, was how you could talk about losing weight and ignore the challenges of keeping it off. It’s not hard to lose weight, it really isn’t.
Weight maintenance is where it’s at right now, not weight loss. And we know that people who lose weight and keep it off, 100 percent of them are very physically active. Physical activity is critical to keeping weight off.
That’s another thing about the article that didn’t make sense to me. It’s a major oversight. Anyone can take weight off. You can shock the human body and you’re going to lose some weight, but you need to keep the weight off. That’s obviously what matters.
Q: The Time author integrated personal anecdotes about his tortured extreme exercise regime over the years amid constant cravings for donuts and greasy French fries, which seemed to color the piece and its conclusions…
A: This was funny because his exercise kept the weight off him, and he kind of missed that point too. Someone in the industry who I really respect said to me, it read like a blog. I’m sorry, but what does this single man living in Manhattan exercising these extreme times, who’s obviously very affluent, what does his experience have anything to do with the average person struggling with weight out there? What does this say to a single mom who has two kids and is working to make ends meet?
I found it a little bit audacious for him to talk about his exercise routine with expensive trainers when he’s not the typical American dealing with weight problems and real everyday challenges.
But what disturbed me more was this off-the-cuff comment deriding the benefits of PE for kids… where did that come from? I thought that was crazy. He could have stuck to the facts and been just as provocative. The truth is a great story here. He didn’t have to say only 75 percent of the story.
Q: Put into perspective for everyone what exactly your study showed.
A: Our study reinforces the idea exercise does not give you carte blanche to eat whatever you want, especially high doses of exercise.
Exercise is effective for weight loss but you also must pay attention to diet. This is another thing theTime author didn’t address. There are a lot of studies showing that when you do large amounts of exercise with the goal of losing weight, if you address diet, you’ll lose the weight you’re expected to lose. That should have been discussed.
Q: What is the story with metabolism? How does one’s metabolism influence weight loss and weight gain?
A: Metabolism is this danger word that people love to talk about. It’s fairly simple. Very, very, very, very few people have this magical low metabolism. That’s kind of a myth. Believe it or not, the number one determinate of metabolism is how big your body is. The larger you are, the more metabolic mass you have and therefore a larger metabolism.
So an obese individual actually has a very high metabolism. And to maintain that weight, they have to eat a lot of calories a day. So when they initially cut say 500 calories or 1000 calories a day out of their diet, they start shedding weight fairly easy. It’s hard to get 500 to 1000 calories of exercise a day.
Initially, when you talk about weight loss, it’s more efficient to lose weight through diet. But then you keep it off through exercise. My thing is, exercise is good for you and you’re going to need to do that eventually anyway, so why not start with that also. As you start to lose weight your daily caloric requirement goes down because you’re losing mass. You’re going to reach a point where you can’t keep cutting calories out of your diet forever. You’ve kind of found your diet place, whether that’s 1,500 calories, or 2,000 calories, it depends on your body size.
It’s obvious then you have to work on the other side of the equation and that is expending calories with exercise. That’s why after you’ve lost weight the relative importance of exercise goes up.
Q: Is there any truth to yo-yo dieting messing up one’s metabolism, causing one to gain more weight back on the rebound?
A: There’s not a physiological reason for gaining more weight back after you’ve lost a lot of weight. I’d avoid going down that road. I think more than anything, those people just eat more.
Q: While some people might reward themselves with sugary, fat-laden snacks after exercise, others might do just the opposite and reach for healthy foods. As far as personal anecdotes, I prefer fresh produce! What about the psychological component of working out? Doesn’t it make one feel better, relieve stress, boost energy, build flattering muscle tone, etc.? Couldn’t these attributes encourage a healthy diet?
A: Absolutely. If there was a pill, we’d all be taking it. Physical activity reduces your risk of dementia, it reduces your risk of depression, it improves your day-to-day quality of life, it reduces anxiety, everything, it just makes you feel better about yourself. This is what we found in our published paper looking at quality-of-life and exercise.
The Time article gave people an excuse not to exercise. I’m not convinced that the role of exercise in preventing weight regain is all about calories in and calories out. I personally think there’s a huge psychological element we need to quantify. When people work out, they feel better about themselves and life and not as inclined to feel better about themselves by eating. That’s an active area of research we need to learn more about.
Q: When you’re doing these studies and analyzing diet and exercise routines, do you find people’s actions connect with their words? For example, in produce industry surveys, consumers might say they’re eating more servings of fresh fruits and vegetables a day, yet sales don’t reflect that.
A: There are many complicated issues in doing this work, and you’re hitting on one. I don’t know how you say this nicely, but they lie. They often think they’re doing things they’re not. That’s why we use the exercise machines, because exercise machines don’t lie.
Q: In the Time article, it references that you ask the subjects in your study to keep their dietary habits the same, yet you point out that particularly in the extreme exercise group, people ate more.
A: Well we didn’t really tell them that. We said do what you want. The study was not specifically designed to look at diet. We’re subsequently trying to get a study funded that is designed to look at weight; things like bringing people into a buffet and watching them eat, and to observe what they’re eating.
Q: It’s interesting that you choose a buffet, because the concept seems to encourage overeating. People want to get their money’s worth, and it’s hard to have will power with all the choices, not to mention controlling portion sizes…
A: We’re going to look at how people change their response to eating at buffets before and after exercise.
Q: Do you have a hypothesis?
A: My hypothesis is that people are going to overcompensate in response to exercise. I think it will all be driven by reward. I don’t even think it takes an extreme workout, it’s the 200 minutes a week, which may sound extreme, but it’s the current recommendation.
Q: How do you change that behavior?
A: Awareness is the start, going through the math. Telling people this is how many calories you burned and this is how many calories are in that muffin. If weight is a concern to you, you’re obviously not making a great decision here.
Q: With all these weight loss strategies, do you find the time of day you eat, and how often can make a difference? Eating a big breakfast, and mini meals throughout the day versus a big dinner late at night, for example?
A: You know, people get really excited about that information and it sells a lot of books, but it really comes down to calories in and calories out, when you take them in doesn’t really make the difference. When you study people who lose a lot of weight, it’s just the basics. I keep having to tell people that. Unfortunately, the truth is boring and the truth doesn’t sell magazines.
Q: Aren’t there studies showing that kids that eat a healthy breakfast reduce frivolous snacking later on, in addition to fueling brain power!
A: In this regard, eating breakfast is critical. We know for people who lose weight and keep it off, eating breakfast is a common behavior.
Q: What can the produce industry take away from this discussion?
A: It seems like the produce industry is not fully at the table with this healthcare reform, and really missing an opportunity. Everybody is really getting excited and energized about taxing unhealthy foods. Let’s help people get better access to healthy foods.
People in the industry need to step forward and say here are five ways the federal government can help get more produce into the hands and mouths of people. Rather than taxing, we’ve subsidized corn for a billion years… what’s wrong with subsidizing fresh fruits and vegetables?
If you want people to lose weight, you focus on a low-fat diet and eating fresh produce is a way to combat obesity. There’s a unique opportunity for the produce industry to bug the hell out of people in Washington to say we need to be a part of this solution. This idea that we’re going to tax our way out of the obesity epidemic is insane to me.
People can’t buy produce if it’s not readily available. Subsidize refrigerators for small stores unable to stock good quality fresh produce, or rather than an ice cream truck coming to these poor neighborhoods, have a big refrigerated truck going into these neighborhoods selling produce.
Q: That’s a catchy idea.
A: It wouldn’t be that hard to pull off, if you had the money to build the infrastructure. I’ve talked to people, who don’t know what a terminal market is, that are buying produce from supermarkets and reselling it. There are a lot of solutions out there.
Q: Changing engrained eating habits can be a challenging endeavor.
A: It is, but we did it with smoking. That to me is a cop out. Someone is not going to walk in their neighborhood if they don’t have sidewalks. Someone is not going to eat fresh fruits and vegetables if they don’t have access to them. Whether it’s in school, at the work place, or increasing availability in neighborhood stores or with rolling vegetable stores I’ve described, there are solutions.
Q: With reduction of smoking, do you think taxing cigarettes was part of it?
A: Certainly it was. But smoking is a different issue. There are phenomenal graphs showing all the things that went into the anti-smoking campaign, and it wasn’t any one thing; it was a lot of small things.
Q: Also, from a medical standpoint smoking is different because it’s addictive…
A: And also, you don’t need it to survive like food. Just like getting people to stop smoking, changing people’s eating habits will involve a lot of small things.
Q: At one point it was cool to smoke, and then it became shameful… the same principle could be applied to eating junk food. Programs we’ve written about like Food Dudes incorporate psychological elements to make it cool for kids to eat fresh produce.
A: The idea that excess sugar is the only answer is naïve. I’m biased because I grew up in a produce family. We have an opportunity to promote a focus on a low fat diet. Eating more fresh fruits and vegetables and avoiding fried foods has such tremendous health benefits. We know these things work and we give it lip service, but the federal government doesn’t take advantage of these things.
Q: The produce industry has marketed the health and nutrition benefits of produce, the antioxidants and super foods phenomena. Should it be redirecting efforts toward the weight issue?
A: All anyone cares about is obesity. All I care about is health, but most people are obsessed with weight and obesity, and that is the flag the produce industry should be waving, something like, nobody got fat eating carrots and broccoli. If you’re not eating fat and sugar, you’ve got to be eating something.
Q: In that regard, what harm would there be in taxing soda? Wouldn’t that help the produce industry?
A: The harm is that it’s missing the point. By the time we figure out this didn’t work, it will be too late. There’s so much energy and enthusiasm behind it, to me when you do interventions, people feel things are being done to them, and if it doesn’t work — which it won’t — people think there’s nothing we can do. If you tax sugar, people will go to fatty foods.
Q: It’s the same concept as regulating elimination of transfats — you need to know what’s replacing them. After all, the substitution could be worse.
A: All the ranting and raving about transfats was way overblown. There’s crazy politics involved in all of this. To some extent the produce industry has missed a major opportunity to market itself as part of the solution here.
Although we think some of Tim’s excursions into public policy lead to cul-de-sacs, his clarification of the Time article and explanation of his work were much appreciated. After all, how often do we get a professor of “health wisdom” to spend time to guide us, much less someone holding a chair named after such a prominent food industry participant.
On the public policy front, although it is true that sugar is heavily subsidized, the purpose of the subsidy, mostly accomplished through strict limitations on the amount of sugar that can be imported, is to raise the price of sugar — not lower it. In all probability, if the government completely withdrew from the sugar industry, the effect would be much cheaper sugar as imports would flood the US. Some of this would substitute for other sweeteners such as corn syrup but, presumably, cheaper sugar would also lead to more consumption, not less.
It is also difficult to quantify the challenge of lack of access to fresh produce and, even harder to quantify the health impact when frozen and canned are considered acceptable substitutes. Even government give away programs are somewhat problematic, typically focusing on high-sugar-content snack fruits and doing little or nothing to get healthy vegetables into the mouths of children.
Still we found the interview with Tim very valuable for several reasons:
First, he tosses aside a lot of shibboleths of weight loss:
● The time of day you eat is not really crucial.
● Only a tiny percentage of people have metabolic problems that make them gain weight.
● Yo-yo dieting may not be the way to go but it is not because it did anything to one’s metabolism.
Second, he points to the futility of pushing good dietary habits without exercise. Although many people lose weight without exercising, virtually nobody keeps the weight off without exercising.
Third, he points to the kind of great structural changes we need in society if we are really to combat obesity. If one wants to get a building LEED-certified you can acquire points for things such as putting showers into the office building. How does that help save energy? Simple… people can’t bicycle to work if they don’t have a place to shower and change. Adding showers to every work place, sidewalks, bike paths, produce trucks just like the Good Humor man going through the neighborhoods, United’s salad bar in every school… all these are structural, societal issues that are designed to make it easier for individuals to succeed at losing and maintaining weight.
Fourth, the produce industry and its focus on health may be missing the marketing boat. People pay lip service to health but are motivated by being slender, having sex appeal, etc.
We’ve always had some issues with the Fruits & Veggies — More Matters slogan. We always thought it was slightly disingenuous as it implied that there was a known health benefit to eating more produce independent of cutting back on other foods. In other words, that somehow one’s health would be enhanced if one kept one’s diet exactly the same but forced oneself to eat an extra ten servings of produce each night before bed.
Although there is interest in the effect of antioxidants and phytonutrients, much of this research is ongoing and the lessons are unclear. With what we know now, eating more produce in addition to one’s normal diet will probably make one gain weight. And that is basically what Tim is saying; it is Calories In/Calories Out that matters.
Yet Tim also provides an insight that might just help the produce industry. Basically the key advantage produce offers is that it is not generally calorically dense; therefore one can eat more of it and still lose weight or avoid gaining weight if one substitutes for more calorically dense foods.
So if the appeal is to weight loss and the advantage is that one can eat many more ounces of broccoli florets than T-Bone, we need a slogan like “Fresh Fruits & Vegetables: Eat More. Weigh Less.”
Many thanks to Dr. Tim Church for setting the record straight on that Time magazine article and for helping us think through such problematic issues.
