Lighten Your Heaviest Gear: You!

Lynn,

I must be missing something. At one place it says "Mean RMR declined significantly, without differing among groups."

In the results section it says "When all subjects were pooled together, absolute RMR significantly increased by 7% …"

Results goes on to say "Furthermore, ST increased absolute RMR by 7% in both…" I would take that to imply that this was not so for the other two groups.

Also "When RMR was adjusted for fat-free mass (FFM) using ANCOVA, with all subjects pooled together, there was still a significant increase in RMR with ST." Again suggesting not with the other two groups.

I am confused abut why the first item I cited says RMR declined, but all others say it significantly increased.

Overall, this article sounds as if it is saying that strength training significantly increased RMR, and the other two groups did not. If that is what is meant, that sounds to me as if strength training exercise is indeed worthwhile in a weight loss sense.

— Bob

"Subjects: Seventy-nine obese males and females were included."

This may be the case for obese people, but I wonder if it applies to non obese, active people as well. I've been around a lot of very active people most of my life and none of them seemed to have any problem with their weight in spite of having VERY hearty appetites. Runners, climbers, divers, all of them(us) had precisely the opposite problem, trying to maintain our weight. You won't see a fat tri athlete, either, and they consume an enormous amount of food. I question whether obese people can exercise enough to make much of a difference to tell you the truth. It all comes back to calories in vs calories out(type of calories is another subject), and if you are engaged in high volume, strenuous exercise it will be all you can do to digest enough food in 24 hours to replace the energy you have expended and repair the tissue damaged in the process. I guess my point here is that perhaps the study needs to include a wider range of subjects than sedentary overweight folks if it is to be of wide benefit to this active community.

> perhaps the study needs to include a wider range of subjects than sedentary
> overweight folks if it is to be of wide benefit to this active community.

A very good point Tom.

Cheers

"At one place it says "Mean RMR declined significantly, without differing among groups.""

I can't find that, so maybe I'm missing something???

"Overall, this article sounds as if it is saying that strength training significantly increased RMR,"

Yes, but in men only. It had no effect on women. Keep in mind, yet again, that RMR is only half of the equation. The other half is appetite which, all other things being equal, will increase with RMR (and AMR, ie RMR plus exercise). No matter how you slice it, you generally need to make a conscious effort to eat less than you burn if you want to lose weight, otherwise increases in hunger will sabotage your goals.

As part of a research study, I had my RMR measured a few years ago over several days (when I was forty five). It averaged 2500 kcals per day (this is resting, so doesn't include kcals burned through activity, which was quite high for me at the time). By all accounts I should have been shedding weight, but because I didn't make any conscious effort to limit my food intake, I actually gained weight. Trust me on this one, increased RMR does not=weight loss. Ya gotta eat less!!!

And yes, we are talking about overweight and obese folks. Fit lean young athletes are in a different category, as are folks trying to maintain weight lost through dieting. In this sense, exercise helps prevent an increase in weight, but it's not so good at aiding in the loss of significant excess weight.

Type of food matters, and more so for diabetics than 'normal' folks. An insulogenic meal is not a big deal to someone who is lean, has good insulin sensitivity and glycogen depleted muscles and liver. An insulogenic meal is really bad if you are already in a 'fed' state, (lean or not) with glycogen stores fully topped up and no exercise in the near future to burn off the excess glucose. Also a bad idea if your insulin sensitivity is low. If you are a type 1 diabetic, the easiest way to maintain tight control over both blood glucose levels and insulin sensitivity is to eat a diet that keeps insulin requirements to a minimum (i.e. low carb), reserving the carbs for correcting hypoglycemic episodes. And of course muscle promoting (and glycogen depleting) exercise is also very important to prevent fat gain in just about everyone.

A few more comments and observations from the strength training in men versus women.

"A significant relationship was demonstrated between training-induced changes in absolute resting metabolic rate and fat-free mass for men but not for women. This differential association between changes in FFM and RMR for men and women, along with our previous finding that absolute and relative RMR changed only for the men in response to strength training, even though both men and women showed similar increases in FFM, indicates a clear difference in gender responses for RMR in response to ST."

This is another piece of clear evidence that increasing your fat-free mass per se, does not lead to an increase in RMR. In other word, both men and women added fat-free mass in similar amounts (1-2kg on average, depending a lot on age), yet only men had an increase in RMR. This can be better seen by looking at the changes in RMR per kilojoule of fat-free mass. In the male groups, the increase was from an average of 111 kJ per kilo of lean tissue to 118 kJ per kilo. So the muscle they already have is working harder than before, rather than the increase in RMR being just an effect of having overall more muscle.

"When all subjects were pooled together, changes in RER (respiratory exchange ratio, an indicator of what kind of fuel is being burned) were positively correlated with changes in fat mass and percent body fat. When these correlations were analyzed by age and gender, RER remained significantly correlated to changes in fat mass for men. Additionally, changes in RER were significantly correlated to changes in percent body in men."

To understand this, you need to know that the lower your RER, the more relative fat you are burning compared to protein or carbs. So the lower the RER, the more fat you burn. Again, women draw the short straw here, as they had a small INCREASE in RER, whereas the men had a significant decrease. Again, although this does not necessarily have anything to do with actual weight loss, it shows that strength training is not as good at getting women to burn proportionally more fat as it is for men.

A synopsis of some of the above research might be helpful. Overall, exercise in general does not contribute significantly to weight loss in overweight folks, but is critical for successful long term weight loss maintenance.

A reduced calorie diet (with or without aerobic exercise) leads to more rapid weight loss, but more of this weight is from muscle instead of fat. Strength training with dieting helps to retain some of this muscle at the expense of slightly slower weight loss. Strength training without dieting leads to a small increase in lean tissue (fat-free mass which includes muscles, organs, fluid and bone), but doesn't lead to weight loss even though in men it leads to and increase in resting metabolic rate and an increase in amount of fat burned as fuel. In women the only metabolic benefits of strength training are a small increase in lean tissue (and strength). This is based on a study of 24 weeks strength training. Bottom line: weight loss in already overweight individuals requires them to make an effort to put less in their mouthes rather than just counting on exercise to work some magic.

One more interesting piece of the puzzle that I just came across is the relationship of resting metabolic rate to obesity. In a large study of lean versus obese adolescents and children, the major determinant of RMR was BMI. The fatter they were, the higher their RMR. Interestingly they looked at the components of fat mass and fat-free mass, and found that the real predictor of RMR was fat-free mass…in other words the obese subjects had significantly MORE fat-free (lean) mass than the lean subjects, and this accounted for most of the extra RMR in obese. Once again this shows that merely increasing your RMR is not enough to either prevent obesity or cure it. This no doubt explains why it is easier for obese folks to lose weight on a calorie restricted diet, while the same amount of caloric restriction in less obese or lean individuals does not cause as much weight loss.

Same goes for guys versus gals. It used to really get under my skin when dieting for bodybuilding competitions. Everyone aimed to cut 500 calories per day from their actual weight maintenance needs, while increasing calorie expenditure by 500 cals worth of exercise. This created 1000 cal per day deficit, which equates to ~ 1kg weight loss per week. The biggest males might have to cut down from 4000 cals to 3500 cals per day, and do half an hour of exercise. Us smaller females had to cut from, say, 2000 cals to 1500 cals per day, and do an hour of exercise to achieve the same rate of weight loss. This is 50% more exercise, and a 25% reduction in calories for the women, but only a 15% cut in calories for the men. I used to have to sit and watch some of these guys shovel in over twice as much food as me, and for sure they weren't feeling as hungry as me!!! No doubt it also explains why female bodybuilders experience such a greater rebound weight gain than the men :(

As a crossfit trainer, I've done my fair share of homework and research, none of which I am willing to point to primarily for one reason: No research on diet has really conclusively proven anything for all populations. Even seeminlgy accepted facts like caloric limiting being the primary cause of weigh lost can be challenged because of the variety of populations, as well as exercise levels and health risks. The conclusion then (even more true after reading this discussion) is that there is no magic bullet for weightloss. I can't point to one thing that will work for everyone. I like Paleo, but that's just me. Especially since I've gone from 230 to 205 which is pretty dramatic for a 23 year old.

What do I suggest to my clients who want to lose wight?

Do your research. Start with Taubes or Pollan, they give a great overview. Read the Zone, Read the Paleo diet, read everything and anything you want, and ultimately consider what will work best for you. It's just like buying a pack. Do your research and consider all the opinions.

Then try it. We call it the "Black Box" Test. It goes like this: if I eat less carbs do I lose weight, feel better and am happier? Then I keep low carb. What about high healthy fat? Very sleepy, upset stomach and angry? then I don't do that. The only one who really knows if I diet works is you.

As to weightlifting, P90x is great but I couldn't do that for 1-1.5 HOURS, especially standing in front of my TV. I found powerlifting vary helpful for hiking, especially with a bad knee, and Crossfit (or any other high intensity program) to be great for improving my wind. I did my research and educated myself about all of this, I use no machines, and I try and work very hard in my workouts

The proof?

The first time I went out hiking (November) after I broke my knee in February I covered 9 miles in 5 hours with a 40lb pack in Pisgah Forest with some pretty rough grades thrown in there. I attribute this speed (with that weight!) to Crossfit.

Two informative NPR stories. Audio and text available.

Rational Or Emotional? Your Brain On Food

Willpower plays a role in dieting. But keeping the weight off after you’ve lost it? This is where our physiology can get in the way. Research suggests that hormone shifts that follow weight loss play a role in changing the way our brain responds to food.

http://www.npr.org/templates/story/story.php?storyId=123894109

Why We Gain Weight As We Age

It’s a pretty common lament, the idea that you just can’t eat what you used to. But why is that so? And is it avoidable? There are a number of reasons why we put on the pounds as years go by, but take heart: There are ways to fight back — and win!

http://www.npr.org/templates/story/story.php?storyId=123887823

Bottom line is that we are concerned about weight, we just have to get off our butts and exercise. And exercise does as much for our brains as it does for our bodies. Not rocket science.

"Bottom line is that we are concerned about weight, we just have to get off our butts and exercise"

+ 1

"It's a pretty common lament, the idea that you just can't eat what you used to. But why is that so? And is it avoidable?"

Definitely avoidable. As Nick posted, "get off your butts and exercise. Simple as that, unless you have an endocrine system problem. It sounds as if Roger C. and his wife have it figured out. Ditto Reinhold Metzger, Alan Dixon, Don Wilson, Will Rietveld, Roman Dial, and Nick Gatel, to mention a few familiar names. I can add my own personal experience to this category. I weighed 139# as a very active freshman in high school who ate anything and everything in sight. I now weigh 137# as a pretty active 69 year old. True, I eat much more carefully, but don't worry about eating too much. When I am satiated, I stop. The one constant, as far as I can tell, is exercise, lots of it. Simple as that, IMO.

Tom! You're 69? Well, I just gained a lot of respect for you, my friend (mainly because my momma told me to respect my elders, and you're a lot elder than me……. ;-)

"and you're a lot elder than me……. "

Eh?? ;}