Tuesday, February 2, 2016

Eat Less Move More doesn't work!

Happy Groundhog Day! 
There are two meanings in the image for today's post: 1) Happy Groundhog Day, being from PA, this is a pretty big holiday - did you wake up to I got you babewe did, and 2) most (all) science papers are written such that no one can understand them and we need to fix that!

Last week after my first rant on bad science, Randy tweeted me a link to this paper.  This one is actually good and describes a very clear result that has incredibly important implications on health policy (though, really we should let theoretical chemists or computational neuroscientists do health research - we do a much better job with our models).  The main point of the paper is eating less and moving more has negligible effects on how many calories you burn.

What? That can't be. Every health, nutrition, fitness, and government source of information you find will tell you to eat a well-balanced diet and get off the couch and move more and we'll solve the nation's obesity problem.

Well, as it turns out, your body is smarter than you are, and it has a ton of buffering mechanisms to be able to deal with variability that once was in our environment, and you really can't outsmart it.  The linked paper above actually does some pretty decent science to show that marginal increases in physical activity (moving more) do not correspond to equivalent increases in the number of calories you burn. We think our bodies work like the additive picture below, but in reality they work like the constrained picture.

image credit: the linked paper above
Our bodies are smart enough to compensate for increased physical activity by not doing something else. That way our total energy expenditure is about the same no matter what we do. Where does that compensation come from? First, here's what the paper says:
Rather than increasing total energy expenditure linearly in response to physical activity, individuals tend to adapt metabolically to increased physical activity, muting the expected increase in daily energy throughput. These metabolic changes can be behavioral, such as sitting instead of standing, or fidgeting less, but they may also include reductions in other, non-muscular metabolic activity. For example, men and women enrolled in a long-term exercise study exhibited reduced basal metabolic rate, and studies in healthy adult women have shown suppressed ovarian activity and lower estrogen production in response to moderate exercise. Other species have also been shown to keep total energy expenditure remarkably constant in response to increased physical activity, reducing energy expenditure on growth, somatic repair, and basal metabolic rate and even reducing lactation and cannibalizing nursing offspring, even when food is available ad libitum and total energy expenditure is well within maximum sustained levels.
Did you read that? I did, but it's not easy - and this is from the introduction when they're "trying" to tell you the big picture - go read the whole thing and watch out when they start to get into the details.  What they are saying is that if you "move more" you don't burn more calories. If you get up early and go for that early morning jog, if you take the stairs instead of the elevator, if you do a two-a-day "cardio" session,  your body will adapt by sitting more throughout the day, or sitting or standing in a posture that uses less muscle.

Did you notice some of the things listed there? Suppressed ovarian activity, lower estrogen production, reduced lactation! I hate the culture of treating women like they're physically and mentally handicapped when they're pregnant, but I also hate the other side of the spectrum when they're glorified for not slowing down and working out even harder. Where should they be spending their energy - growing a baby or going all-out in a workout? (Not to say that pregnant women should give up on fitness and do nothing - just that it's not a time for PRs and intensity.)

Other things listed: reducing energy on growth and somatic repair. What does that mean? You won't get bigger nor will your body repair itself. The eat less, move more philosophy means your body will be breaking itself down and not fixing itself. That doesn't sound healthy to me.

But, I digress, the main point of my rant is that none of this is written clear enough for an average reader to understand it. When I was in grad school, I remember talking to my adviser about writing papers and the most important thing was keeping the information-to-ink ratio really high. As a computer scientist I viewed this as a form of data compression. We take lots of time to pick just the right terse phrases so that the paper packs tons of information into a small space and then the reader spends lots of time unpacking those phrases to understand their meaning. Maybe in the days of paper publication this was a good thing, but now electrons are cheap. Scientific papers should be legible, not terse and technical just for the sake of sounding smart.

I'm not picking on this paper specifically, I'm just using it as an example of why our nation as a whole is getting sicker and more obese while working harder each year. I've been trained in reading scientific articles, and still my eyes glazeth over when I read them. What's a lay person going to do? Some over-worked random staffer in the government is also going to skip this and let policy just dictate what they feel the constituents want to hear.

Health, fitness, and nutrition are too important to be behind a wall of smart-sounding science-y stuff. We need to put the effort in to communicate in a way that everyone understands. We need to get our policy makers to understand so they can make clear recommendations (though, that may be asking too much from the government). Next time someone throws out jargon and scary big words trying to sound smart, ask them to explain in normal language. One of two things will happen, they'll gladly explain it in your language because they care about getting their ideas across. Or they'll get even more jargony to seem smart because they really don't know what they're doing.
strength - add weight from last time (more info) 

3 attempts for max push-ups 


20-19-18-...-3-2-1 KB Snatch

1-2-3-...-18-19-20 Box Jump