Monthly Archive: July 2012

High Reps and Low Weights vs Low Reps and High Weights: which is better?

This is an argument that you read a lot of Tumblr. We all decry the “20 reps, 5 lbs, LETS GO!” method of working out, especially for women, for many reasons. Some will say it’s sexist, it doesn’t work, it takes forever, etc. The current Tumblr Train is to lift heavy and love it.

You know I was going to throw some SCIENCE at you.

There’s a recent study that says both are equally effective at increasing muscle mass.

NOT SO FAST! This is where your critical thinking skills come into play.

The study design is this: using leg extensions, measure short-term elevations in protein synthesis and the cross-section of muscles with high reps at 30% of max vs. low reps at 90% of max. So if your max leg extension is 100 lbs, you’re going to do 30 lbs for high reps or 90 lbs for low reps. Here’s the kicker: you do them to fatigue. That means you’re going to plus away on that exercise until you can’t squeeze out another rep.

Problems: Leg extensions are kind of a horrible exercise for this because it’s not a compound exercise, it’s an isolation one. Using the trifecta (squat, dead, bench) may have been a better option to really assess how this plays out. Additionally, short-term protein synthesis isn’t the ONLY factor in determining muscle growth. It’s just a small frame in a very long, complex movie.

So how can we interpret this?

Say we accept that this is true – that doing 30lb leg extensions until you can’t any more and doing 90 lb leg extensions until you can’t anymore will build the same amount of muscle. Why should you stick to the heavier weight?

Time.

How long do you think it takes to get to fatigue repping out 30 pounds versus repping out 90 pounds? I personally don’t see the point in sitting on the same machine for 20 minutes when I can get the same results in a shorter span of time. While I do enjoy spending a lot of time at the gym (it’s my heaven) it seems silly to machine hog for 10-15 minutes when I can do something else.

Yeah, you can wash your hair with a spray bottle, but just hopping in the shower will get the job done just as well in a shorter amount of time.

Take home message: As long as your train to fatigue it doesn’t matter what weight you’re using. However, using a heavier weight means less time spent for the same results.

July 4, 2012 Exercise, Myths Read more >

Can you really lengthen your muscles, or is that a lie?

This comes from the myth of “toning,” which we’ll address some other time, but how many of you have heard this? Said this? The idea is to do exercises that burn fat while making your muscles look “long and lean.” Here’s the deal.

Muscles only grow one way: in diameter.

When muscles grow it is referred to as “hypertrophy.” Hypertrophy literally means an increase in cell size, versus hyperplasia which means an increase in cell number. Muscles cannot undergo hyperplasia, only hypertrophy. So when you’re increasing muscle mass you’re doing so by increasing the size of the individual cells in the muscle.

Additionally, let’s look at the physiology of muscles. Muscles are attached to bone at very specific spots, and are made up of muscles and tendons, plus other contractile proteins. Any medical student will roll their eyes and spew out the long list of origins and insertions, plus various attachments, of every muscle in the body they had to learn in anatomy. Knowing this, how do you increase the length of a muscle without changing the attachment of the muscle? It doesn’t make sense. It would imply that something else has to change too – like the ligaments or tendons it’s attached to would have to shorten in contrast, or the length of the bone would have to change to accommodate this new “length” in muscle to still allow the body to function normally.

Basically, picture a muscle on a bone. Now imagine that muscle growing in length, while nothing else around it changes. Doesn’t really work, does it?

When most medical texts refer to muscle length they’re referring to the tension of the muscle (usually using torque). When adding stretching routines to your workout (yoga, pilates, etc) that increased flexibility is a decrease in the slop of the angle/torque curve, or shifting that entire curve to the right. This is done by stretching the muscle, not by adding length or by somehow making the “bulkiness” of the muscle translate into longer muscles, not fatter muscle cells.

If you’re building muscle you’re building it one way: in diameter. Decreasing the fat that is covering your muscles is the only way for the muscle to appear “long” versus “bulky.”

July 4, 2012 Exercise, Myths Read more >

Where does fat go when you lose it?

What is fat?

Fat is extra energy that we store on our bodies. Any time you eat more than your body burns, that excess energy is converted into a storage form and placed various places in your body. The most problematic of these aesthetically (and health wise) is in fat cells, which translate to the padding you carry on your body. Some body fat is healthy and necessary – women require a certain amount in order to produce hormones necessary to maintain their period and become pregnant. Too much fat can be detrimental to our health.

Fat cells

Fat cells are located throughout our body and increase or decrease in size. The average human has 10 billion to 30 billion fat cells located around their body. An obese person can have up to 100 billion. Usually, fatty acids are stored inside these fat cells, making them increase in size. This tends to be genetic – certain people gain and lose fat in certain areas preferentially over others. It’s possible for your body to increase the number of fat cells on their body when they become obese. However, there is no way to “lose” fat cells. When you lose fat off your body, you’re shrinking the size of the fat cells, not getting rid of them.

How do you get rid of fat cells?

Liposuction is the only way to actually remove the fat cells. Otherwise, they remain deflated throughout your body.

So what happens when you lose fat?

Like I said above, the fat cells shrink. If you create a caloric deficit your body pulls energy from these storage forms of fat and uses that. As it pulls the energy out of the fat cells they shrink. That fat is used for energy, and the byproducts are excreted in your urine or feces.

Can the fat cells increase in size again?

Yes. If you start consuming more energy than your body can burn your fat cells will increase in size as that extra energy is stored in them.

July 4, 2012 Exercise, Fat Loss, , Read more >

Does your metabolism ever recover from having an eating disorder?

As someone who’s recovered from an eating disorder this topic has plagued me for a long time. You hear horror stories of yo-yo dieters that are unable to lose weight because years of starvation lead to a metabolism that basically doesn’t work anymore. I’ve often said things myself such as, “I probably screwed up my metabolism for life!” or “These years of dieting have really done me in.” I decided to get rid of these thoughts and instead search through my great old buddy, PubMed. PubMed is a giant database of scientifically published articles about anything and everything science related. So I took an entire afternoon researching how metabolism fairs long-term and short term in recovering anorexics.

My first study looked at the differences between resting energy expenditure (REE, you may be used to calling this your BMR) and respiratory quotient (RQ) between recovered anorexics who’ve been recovered for 2 years and women who were never anorexic. The conclusion? No difference. Recovered anorexics had a higher rate of fat oxidation (the body’s ability to break down big fat molecules and use them for energy), but even then the differences in body composition were basically null. Anorexics two years out of recovery had about the same BMR as those who were never anorexic.

I didn’t stop there.

This study on adolescents followed anorexics during starvation and during refeeding. This study is slightly older (1997) but has been a source for a lot of research since then. They compared the theoretical BMR/REE of starving anorexics using the Harris-Benedict equation and found that anorexics had an even LOWER BMR/REE than they thought. When you’re starving, your BMR/REE is lower than hypothesized. As the study went on they re-did this measurements. They found that their BMR increased significantly within the first two weeks of refeeding (anywhere between 72-85% of what was predicted based on the previous equation mentioned). In conclusion, anorexics who are fasting/starving have a lower BMR to adapt to decreased food intake. As they were refed, their BMR increased within predicted parameters. It’s important to note, too, that it had no affect on energy intake or thyroid function.

What about in those of us who are within the first weeks of recovery and are slowly gaining weight? How much of that is fat?

This study didn’t directly test that, but gave some important evidence to suggest an outcome. The main purpose of this study was to find a good way to track weight gain. Should skin fold tests or underwater weighing be used? Any of us who’ve used an online calculator or BMR know that those things can tell us 8 different numbers on any given day. This study was similar. They found that 55.5% of weight gained back was fat. Ouch. But don’t fret – look at the previous studies. It levels out. Reading into the conclusion they hypothesized that this was mostly due to the fact that anorexics often have EXTREMELY low body fat percentages. To gain weight and only half of it be fat isn’t really as bad as it seems. Plus, this study found that anorexics had a high use of carbohydrates during overnight fasting. Basically, anorexics metabolized carbohydrates at a higher rate than normal. It makes sense that refeeding would lead to a higher gain in fat.

And finally, the Holy Grail in these studies was one done in 1991.

This study looked at calorie requirements for weight maintenance of anorexics and bulimics. They took anorexics who were 4 weeks into recovery and at 95%-100% of normal body weight vs. bulimics who were 1-4 weeks into recovery and at a normal body weight and compared their caloric intake and weight gain. The results?

After weight restoration, restricting anorexic patients required significantly more calories per day to maintain weight than did bulimic anorexic patients, as measured with corrections for weight, body surface area, and fat-free mass. Previously anorexic normal-weight bulimic patients required significantly more calories per day to maintain weight than never-anorexic normal-weight bulimic patients, as measured with correction for weight but not with the other factors used to correct caloric intake

Now, this study came with some caveats in the conclusion.

Differences in caloric needs between normal-weight bulimic patients with and without histories of anorexiamay depend on the methods used to correct caloric requirements. Body surface area may be the most precise correction factor across different subgroups of eating disorder patients. Elevated caloric requirements, when coupled with reduced food intake, may particularly contribute to relapse in anorexic patients.

Did you guys read that last part? Remember that every time you feel a relapse. There are medical reasons behind these feelings, they are normal.

In conclusion – I was wrong. My metabolism is not permanently screwed up. Neither is yours. Initially we gain back weight that was important for our survival, as shown by how low our metabolism got when we were at our sickest. After that? Our metabolism and body requirements mirror those of people who NEVER suffered through an eating disorder. Who else can benefit from these studies? Yo-yo dieters, chronic dieters, people trying to slowly go into Intuitive Eating…these studies cross a wide range of potential eating issues.

Recovery is possible. It’s a long term uphill battle and never an overnight thing. Give your body time to adjust, your mind time to adjust, and find lots of support and love amongst those around you. You have time to turn your life around, it’s never too late.

July 4, 2012 Metabolism Series, Read more >

How long until my metabolism drops from fasting?

I think I know where this information came from – The Minnesota Starvation Study. Matchstick Molly does a great breakdown of this study, but in essence they took a bunch of middle aged, totally healthy guys and over the course of 6 months studied how they responded to a diet that was 50% of their daily intake needs. Basically, if the men required 2,000 calories a day to survive, they put them on 1,000 calories a day. What did they find? Their metabolism decreased by 40% – something that stayed that way for about 8 weeks after normalizing the diet. But this is a topic for another part of the metabolism series, so we’ll come back to that. This “fact” is talking about fasting after all!

How long does one need to fast before their BMR (basal metabolic rate, i.e. the amount of calories it takes you keep you alive if you lay in bed all day and don’t move) drops?

This study found that after 3 days of starvation (i.e. no food, just water) your metabolic rate INCREASES, in fact by about 1 kJ/minute (1kJ = .239 calories). This study also shows the same thing – 36 hours into the fast the BMR INCREASED, at 72 hours the BMR was about the same as it was 12 hours into the fast.

It’s not all roses and sunshine though – this study took a few healthy weight females and put them on a 48 hours fast, then measured how they responded to refeeding. It showed that 40-90 minutes after being fed after the 48 hour fast their body had a decreased metabolic rate. This means the thermogenic property of food (covered in future articles of this series) wasn’t as high as it was in other people who didn’t fast. Still: no 40% decrease in metabolism after 12 hours of fasting.

When does your BMR decrease, though? I mean, it can’t just rev and rev away, otherwise you’d die ASAP.This study shows an 8% decrease after 74 hours. So it took 3 days of ZERO food for your BMR to drop a measly 8%.

Another study for your reading can be found here. This one found your BMR increases 3.6% after a 48 hour fast. This is old hat now- you guys know this. BMR increases, then decreases after 74 hours by 8%.

Moral of the story? Your BMR will initially increase during the first 3 days of fasting by about 3-4%, then it will decrease 8% after 3 days of fasting.

I’m calling this “40% decrease in metabolism after 12 hours” a big fat FALSE.

July 4, 2012 Metabolism Series, Nutrition, , , Read more >