Tag: weight loss

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My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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UCLA researchers are reporting a study on how one of the ingredients in hot peppers can enhance calorie burn and fat oxidation for several hours after a meal. That’s sort of old news — what’s new is that instead of capsaicin they’re using another substance called dihydrocapsiate (DCT), which is like capsaicin but doesn’t make smoke come out your ears when you eat too much. So in other words, they’re saying: “Look, we can get all the benefits without the downside!” I don’t even have to read the study to know that’s not going to work out as promised. (Or maybe that’s just my Puritan streak emerging!)

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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In the comments section of an earlier post that mentioned the potential caloric benefits of standing as opposed to sitting, Peter asked how sitting on an exercise ball stacks up. The news is good. A 2008 study in the European Journal of Applied Physiology by researchers at the University of Buffalo compared energy use during clerical tasks while sitting in an office chair, sitting on an exercise ball, or standing up. Subjects burned 4.1 calories more per hour (a 6% boost) when they were either standing or sitting on the exercise ball compared to sitting in the regular office chair. There was no difference between standing up and sitting on the exercise ball. The numbers are consistent with a 2006 study that found a 3.9 calorie per hour (5.6%) boost for exercise balls, with effects that persisted for at least a week.

Presumably, this enhanced calorie gain has the same benefits as standing — that it doesn’t trigger your appetite hormones to make you compensate. On the other hand, some back experts are still cautious about the effects of sitting on exercise balls all day. Stuart McGill of the University of Waterloo, for instance, did a study in 2006 with the following conclusions:

The results of this study suggest that prolonged sitting on a dynamic, unstable seat surface does not significantly affect the magnitudes of muscle activation, spine posture, spine loads or overall spine stability. Sitting on a ball appears to spread out the contact area possibly resulting in uncomfortable soft tissue compression perhaps explaining the reported discomfort.

So, as long as your back doesn’t start bothering you, the exercise ball seems like a reasonable choice. And you don’t have to worry about your productivity, at least according to the University of Buffalo study: in 20 minutes, the men in the study typed 551.8 words on the exercise ball, 535.6 words while standing up, and 519.2 words while sitting in the office chair. (The women were much consistent, at 700.3, 697.8 and 702.5 respectively.)

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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I’ve posted a few times recently on the challenges of losing weight — in particular, the homeostatic mechanisms that your body uses to fight against any attempt to burn more calories than you consume. For instance, exercising stimulates appetite hormones that prompt you to eat more. So I found the following tidbit in the New York Times interesting:

In a completed but unpublished study conducted in his energy-metabolism lab, [Barry] Braun [of UMass-Amherst] and his colleagues had a group of volunteers spend an entire day sitting. If they needed to visit the bathroom or any other location, they spun over in a wheelchair. Meanwhile, in a second session, the same volunteers stood all day, “not doing anything in particular,” Braun says, “just standing.” The difference in energy expenditure was remarkable, representing “hundreds of calories,” Braun says, but with no increase among the upright in their blood levels of ghrelin or other appetite hormones. Standing, for both men and women, burned multiple calories but did not ignite hunger. One thing is going to become clear in the coming years, Braun says: if you want to lose weight, you don’t necessarily have to go for a long run. “Just get rid of your chair.”

This suggest that all those people trying to work at “stand-up” desks may be onto something. On the other hand, I’m still not completely sold on the general message about exercise and weight loss that is more or less accepted as fact in this article:

“In general, exercise by itself is pretty useless for weight loss,” says Eric Ravussin, a professor at the Pennington Biomedical Research Center in Baton Rouge, La., and an expert on weight loss.

The article then describes one of Ravussin’s studies (which I blogged about back in December) in which one group of subjects lost nearly 10% of their bodyweight, or a pound a week, through exercise alone — which seems to contradict the assertion that exercise is useless for weight loss.

But in the exercising group, the dose of exercise required was nearly an hour a day of moderate-intensity activity, what the federal government currently recommends for weight loss but “a lot more than what many people would be able or willing to do,” Ravussin says.

Oh, now I get it. It’s not that exercise is useless for weight loss — it’s doing a little bit of exercise at a low intensity that is useless. Those are two very different statements. I understand that an hour a day of moderate-intensity exercise is a tall order for people in today’s busy, convenience-driven, nutritionally bankrupt society etc. etc. But that doesn’t mean exercise is useless, it just means that it takes a lot of exercise — more, perhaps, than most people are willing to do — to see appreciable changes.

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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In response to a recent reader e-mail:

My question is the following: is it better to eat three meals per day or is it better to eat several small meals throughout the day? I am currently weight training a few times per weeks and I am also trying to lose some weight. Ideally, I want to lose some fat while also gaining some muscle.

This debate has bounced back and forth since at least the 1960s (when some key papers were published in Lancet and the American Journal of Clinical Nutrition). The latest take comes in a study by researchers at the University of Ottawa that will appear in a forthcoming issue of the British Journal of Nutrition. The basic idea is that eating more frequently might keep you feeling more full, possibly by preventing big swings in the gut hormones that influence hunger:

Increased feeding frequency has often been proposed to convey favourable effects on body weight, adiposity and energy intake, but controversy persists. It has been hypothesised that the favourable effect of increased meal frequency (MF) could emanate from a more sustained release of gastrointestinal hormones; however, more studies are needed to confirm this postulation.

In this study, they put 16 obese volunteers on diets with identical caloric deficits for eight weeks. Half of them ate three meals a day, while the other half at three meals plus three snacks. The results: no difference. Or, in science-ese:

The premise underlying the present study was that increasing MF would lead to better short-term appetite regulation and increased dietary compliance; furthermore, it was hypothesised that these predicted beneficial effects of increased MF could have resulted from more favourable gut peptide profiles, potentially leading to greater weight loss. Under the conditions described in the present study, all three hypotheses were rejected.

Now, only a fool would think that, after nearly half a century of conflicting results, the newest study must be the truest. This is just one more data point. But it suggests to me that there isn’t compelling evidence either way — so the choice is up to you. Personally, I snack.

(Thanks to Jim for the question, and to this NYT article for the pointer.)

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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I posted earlier this month on “why weight loss isn’t just calories in minus calories out,” which led to an interesting discussion on the ways in which the body tries to prevent itself from gaining or losing weight. On that topic, I came across an interesting study published earlier this year in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, from researchers at Columbia University. The gist: it’s the efficiency of our muscles, on a cellular level, that conspires to hold our weight steady.

It’s well-known that, if you lose weight, your metabolism slows down to burn fewer calories. (That’s why, as a recent JAMA paper pointed out, eating one less 60-calorie chocolate-chip cookie per day won’t allow you to keep losing weight forever. Instead, if exercise and other factors are kept constant, you’ll plateau after a few years at a weight six pounds lighter.) Part of that is because, as Phil Koop pointed out, “adipose tissue has a metabolic cost.” Or as the JAMA paper puts it:

A person who consumes an extra cookie every day will initially experience weight gain, but over time an increasing proportion of the cookie’s calories will go into repairing, replacing, and carrying the extra body tissue.

But the Columbia paper makes it clear that the extra tissue, on its own, isn’t enough to explain the changes in how many calories you burn:

Maintenance of a body weight 10% below “usual” for a lean or obese individual is accompanied by a reduction in systemic energy metabolism (~300–400 kcal/day less than that predicted solely on the basis of changes in body weight or composition), neuroendocrine function (decreased circulating concentrations of leptin and of bioactive thyroid hormones), autonomic nervous system physiology (decreased sympathetic nervous system tone and increased parasympathetic nervous system tone), and behavior (decreased satiety) that act coordinately to return body weight to its initial level.

To figure out where these missing calories go, the Columbia group has been doing extremely careful experiments that involve checking volunteers into an inpatient research clinic for several months at a time, and feeding them only a liquid diet (40% corn oil, 45% glucose, 15% casein protein, by calories) so they can precisely monitor energy intake. They control the amount of feeding to make the subjects gain or lose 10% of their body mass, then study the changes to their metabolism. Pretty neat stuff.

Anyway, the major finding of this new study is that “skeletal muscle work efficiency” changes dramatically when you change your body weight. It’s not just because your muscles have less weight to carry around — it seems to have more to do with changes in the ratio of enzymes that determine whether the muscle burns carbohydrate or fat. When you lose weight, your muscles get more efficient — which seems like a good thing, except that it means you burn significantly fewer calories when you move around, which pushes your weight back up. The opposite happens when you gain weight: your muscles get less efficient.

So what’s the take-home (other than “Try not to gain weight, because it’s really hard to lose once you do.”)? Because the ratio of carbohydrate-to-fat utilization depends on the intensity of physical activity, there’s reason to believe that the efficiency changes are only relevant at very low intensities — corresponding to the activities of day-to-day life as opposed to “exercise.”

From a therapeutic standpoint, exercise post-weight reduction might be more effective at higher workloads, i.e., that the weight-reduced individual might “escape” this increased efficiency by altering the intensity of exercise even without necessarily increasing the work performed.

In other words, exercise harder rather than longer might be the most effective strategy for keeping weight off.