Exercise, Uncategorized
August 12, 2009
“In general, for weight loss, exercise is pretty useless…”
I must say, I was pretty much speechless after reading this statement (and it isn’t easy to leave me speechless!). After all, this wasn’t some weirdo quack making the kind of absurd comments you often see on the Internet. Rather, these are the words of a man named Eric Ravussin, chair in diabetes and metabolism at Louisiana State University. If nothing else, the man has credentials.
The statement by Ravussin appeared in a recent Time magazine article written by John Cloud and titled, Why Exercise Won’t Make You Thin. As you may have guessed, the article attempts to make a case that exercise is unnecessary for weight loss. In fact, Mr. Cloud, infers that an intense workout might actually hinder your weight loss efforts! Could this actually be true? Should we ditch the gym and go back to being a country of interactive couch potatoes in our quest to be lean? Let’s take a look at the major points made in the article and see what conclusions can be drawn from actual research…
A primary contention of the article is that working out is ineffective in promoting weight loss because exercise makes people hungry. Here is the author’s claim:
The basic problem is that while it’s true that exercise burns calories and that you must burn calories to lose weight, exercise has another effect: it can stimulate hunger. That causes us to eat more, which in turn can negate the weight-loss benefits we just accrued.
Let’s say for a moment that this claim is actually true and that an exercise session sends us straight to the fridge for that leftover piece of cheesecake. Do we thus conclude that exercise is superfluous for those trying to lose weight? If so, I guess we shouldn’t go to the movies since people tend to fill up on buttered popcorn and Bonbons when they’re watching a flick (blame Hollywood for our beer guts and saddlebags!).
Really now, just because you’re hungry following a workout doesn’t mean you have to binge on junk food. I don’t think I’m breaking any new ground in stating that there are many nutritious food-choices available that won’t pad your love handles. It’s is well known, for instance, that consuming protein has a satiety-inducing effect. High protein foods such as lean poultry, fish, and/or eggs not only help to fuel training (those involved in exercise have been shown to need about double the protein of sedentary individuals), but also to aid in quelling hunger. Ditto for fiber rich foods, which fill you up without filling you out. A hearty chicken or tuna salad eaten post-workout will provide a terrific source of nutrients and abolish any thoughts of downing that pint of Ben and Jerry’s sitting in the freezer (and why do you have ice cream in your house when you’re trying to lose weight anyway?).
Now let’s return to the original supposition that exercise makes you hungry. Is there really evidence to show such a phenomenon? The prevailing body of research says there’s not. In fact, the opposite appears to be true. A study by Martins and colleagues (1) had subjects perform moderate aerobic exercise for an hour and then assessed hunger both by self-reported hunger scores as well as measuring various “satiety-related hormones” (i.e. PYY, GLP-1, PP). The result? Self reported hunger showed no significant changes in fullness (‘How full do you feel?’) or motivation to eat (‘How much do you feel you can eat?’) in response to exercise. Moreover, there was an exercise-induced increase in levels of PYY, GLP-1 and PP, which have been shown to reduce the urge to eat. Bottom line: there was no evidence of either physiological or psychological indices of increased hunger from exercise. If anything, there was a trend for greater satiety.
A more recent study at Colorado State University came to similar conclusions. Ballard and colleagues (2) measured levels of the hormone ghrelin after an 80 minute bout of resistance training. Ghrelin has been called the “hunger hormone” – as ghrelin levels rise, so does the urge to eat. Well, surprise, surprise, ghrelin levels fell 13 to 21% as a result of the training protocol, leading researchers to conclude “weight lifting lowers plasma ghrelin concentrations during exercise and attenuates its rise during the postexercise period in young men.”
So, you might ask, how is it then that some people don’t show significant weight loss from exercise? This was addressed in a very well done study by King and colleagues, appearing in the International Journal of Obesity (3). The study showed that a 5-day-a-week moderate-intensity exercise program designed to expend 500 calories per session resulted in an average weight loss of more than 8 pounds after 12 weeks of training. What was most interesting, however, was that there was a huge variability between subjects, ranging from a loss of a whopping 32 pounds in one individual to a gain of almost 4 pounds in another. The researchers went on to conclude that some people are compensators, most likely choosing to binge out after exercise not because they are hungry, but rather as a “reward” for being active. The problem, therefore, is not in using exercise as a weight loss tool; it’s in educating the compensators on strategies to avoid compensating. Exercise works, just don’t feel you’re entitled to munch out because you spent a half-hour on the treadmill. If you want a reward, buy yourself a new dress that’s two sizes smaller–that will keep you motivated to stay away from the fridge!
Another glaring problem with the Time Magazine article is that there’s no distinction made between the types of exercise performed and their effects on weight management. Specifically, resistance training has been shown to be crucial in accelerating fat loss. During dieting, approximately 1/3 of weight lost is from muscle tissue. Since muscle is highly correlated with metabolism, consistent dieting gradually lowers resting metabolic rate, making further weight loss difficult to impossible. Cardiovascular exercise does little to preserve lean body tissue. Lifting weights, however, not only attenuates the decline in metabolism, it can actually increase it (4-7).
Nowhere is this better exemplified than in a study conducted by Ballor and colleagues at the University of Michigan (8). Forty obese women were assigned to one of four groups: diet only, weight-training only, diet plus weight training, and a control (no diet or exercise). After 8 weeks, the diet only group lost the most weight (just under 10 pounds) while the diet plus weight training group came in a close second at approximately 8.5 pounds. The more important statistic, however, was that lean body mass decreased by 2 pounds in the diet-only group, while it *increased* by over 2 pounds in the diet plus weight training group. This not only means that those who lifted weights lost significantly more body fat during the protocol, but that they had a superior body composition.
The Time Magazine article pooh-poohs the metabolic benefits of muscle, citing a Columbia University study that concluded a pound of muscle burns only about six calories a day at rest. This led the Time author to say:
…Which means that after you work out hard enough to convert, say, 10 lb. of fat to muscle — a major achievement — you would be able to eat only an extra 40 calories per day, about the amount in a teaspoon of butter, before beginning to gain weight. Good luck with that.
While this makes good copy, other studies seem to show that muscle possesses greater metabolic properties than those found at Columbia. Much greater. In a study done at Tufts University (9), Cambell and colleagues reported an increase in lean body weight of 3.1 pounds after 12 weeks of strength training increased resting metabolic rate by approximately 6.8%. This translated into an additional 105 calories burned per day. Do the math, and that equates to approximately 35 calories burned for each pound of added muscle. A study by Pratley and colleagues (10) came to a similar conclusion on the topic. A similar four month strength training protocol resulted in a gain of 3.5 pounds of lean muscle. Metabolic rate showed a resulting 7.7% increase, correlating to a metabolic-heightening effect of muscle of approximately 34 calories.
Taking the results of these studies into account, that same 10 pound gain in muscle cited in the Time article would conceivably help to burn an additional 350 calories a day, which would translate into a weight loss of about 36 pounds in a year by simply maintaining this level of muscularity. Even if the actual effects are only half those found in these protocols, that’s still pretty impressive in my book…
Perhaps most importantly, what the Time article seems to completely ignore is the fact that exercise has been shown to be extremely important for maintenance of goal weight after weight loss. Clearly, those who exercise show an improved ability to sustain lower levels of body weight and avoid weight regain after dieting (11-13). And ultimately the most important aspect of weight loss shouldn’t simply be to lose the weight, but rather to keep it off over the long haul.
Summing up, there is compelling evidence that exercise is not only a beneficial aspect of any weight loss program, but it’s crucial in long-term weight maintenance. Despite what you might have read in Time, don’t ditch your gym membership just yet…at least if you want to stay lean!
Stay Fit!
Brad
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1) Martins C, Morgan LM, Bloom SR, Robertson MD. Effects of exercise on gut peptides, energy intake and appetite. J Endocrinol. 2007 May;193(2):251-8.
2) Ballard TP, Melby CL, Camus H, Cianciulli M, Pitts J, Schmidt S, Hickey MS. Effect of resistance exercise, with or without carbohydrate supplementation, on plasma ghrelin concentrations and postexercise hunger and food intake. Metabolism. 2009 Aug;58(8):1191-9.
3) King NA, Hopkins M, Caudwell P, Stubbs RJ, Blundell JE. Individual variability following 12 weeks of supervised exercise: identification and characterization of compensation for exercise-induced weight loss. Int J Obes (Lond). 2008 Jan;32(1):177-84.
4) Bryner Rw, et al. Effects of resistance vs. aerobic training combined with an 800 calorie liquid diet on lean body mass and resting metabolic rate. J Am Coll Nutr. 1999 Apr;18(2):115-21.
5) Donnelly JE, et al. Muscle hypertrophy with large-scale weight loss and resistance training. Am J Clin Nutr. 1993 Oct;58(4):561-5.
6) Ryan AS, Pratley RE, Elahi D, Goldberg AP. Resistive training increases fat-free mass and maintains RMR despite weight loss in postmenopausal women. J Appl Physiol. 1995 Sep;79(3):818-23.
7) Hunter GR, Byrne NM, Sirikul B, Fernández JR, Zuckerman PA, Darnell BE, Gower BA. Resistance training conserves fat-free mass and resting energy expenditure following weight loss. Obesity (Silver Spring). 2008 May;16(5):1045-51.
8 ) Ballor DL, et al. Resistance weight training during caloric restriction enhances lean body weight maintenance. Am J Clin Nutr. 1988 Jan;47(1):19-25.
9) Campbell, W., M. Crim, V. Young and W. Evans. Increased energy requirements and changes in body composition with resistance training in older adults. American Journal of Clinical Nutrition 60: 167-175, 1994
10) Pratley, R., B. Nicklas, M. Rubin, J. Miller, A. Smith, M. Smith, B. Hurley and A. Goldberg. Strength training increases resting metabolic rate and norepinephrine levels in healthy 50- to 65-year-old men. Journal of Applied Physiology Jan;76(1):133-7.
11) Wang X, Lyles MF, You T, Berry MJ, Rejeski WJ, Nicklas BJ. Weight regain is related to decreases in physical activity during weight loss. Med Sci Sports Exerc. 2008 Oct;40(10):1781-8.
12) Miller WC, Koceja DM, Hamilton EJ. A meta-analysis of the past 25 years of weight loss research using diet, exercise or diet plus exercise intervention. Int J Obes 1997;21:941–947.
13) Curioni CC, Lourenço PM. Long-term weight loss after diet and exercise: a systematic review. Int J Obes (Lond). 2005 Oct;29(10):1168-74.
Uncategorized
August 5, 2009
For years I’ve been speaking out about the illogicality of trainers who advise clients to “hollow their midsection” when doing crunches. The theory behind such advice is an attempt to target the transversus abdominis, a deep abdominal muscle that forms a corset around the midsection. Problem is, it’s backwards thinking.
Dr. Stuart McGill, one of the foremost researchers on back health, elucidated the perils of the “hollowing” recommendations in a recent issue of the New York Times Magazine. “In research at our lab,” he states, “the amount of load that the spine can bear without injury was greatly reduced when subjects pulled in their belly buttons” during crunches and other exercises.
Kudos to Dr. McGill, who clearly comprehends the importance of taking a holistic approach to training. It’s imperative to understand that muscles function as a unit, not in isolation. Putting too much emphasis on one muscle while ignoring others is a recipe for poor core health and quite possibly lower back problems. Moreover, altering proper exercise form in an attempt to recruit a particular muscle can in itself place the body in an injurious position. Like I mentioned, backwards thinking.
As Dr. McGill goes on to say, “a core exercise program should emphasize all of the major muscles that girdle the spine.” Bingo! And what are the primary core muscles? They include the multifidi, the erector spinae, the quadratus lumborum, the rectus abdominis, and the deep muscles of the abdominal wall (obliques and transversus abdominis). Sure, the transversus is important for core health, but no more so than any of the others.
As for integrating this into a comprehensive routine, focus on training the core from multiple angles in multiple planes. This will help to ensure complete muscle development of the region. Low to moderate reps help to develop absolute core strength, while higher rep sets and static hold moves (such as plank and side bridge) develop core endurance: both are important for a healthy core. And when it comes to performance, forget the “hollow your abs” or “suck in your belly button” advice; it’s faulty interpretation of research that will only serve to impair muscle development and create imbalances between core musculature. Backwards thinking.
Stay Fit!
Brad
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Uncategorized
August 4, 2009
Want to get rid of cellulite? Then perhaps you’ve thought about using one of those magic creams or treatments designed to smooth out the afflicted area. If so, think again.
As almost every woman knows, cellulite is the term for the dimple-like formations that appear in fatty parts of the body, most often the butt and thighs. What most don’t realize, however, is that cellulite tends to be hereditary; if your mother and siblings have it, chances are good that you will too. Like your height, eye color and hair texture, genetics dictate where fat is deposited and the semblance that it takes on your body. Hence, while some women can be obese with little evidence of cellulite, others can be relatively thin and have cottage cheese thighs.
Why can’t a cream or pill help to reduce cellulite? Because cellulite is actually related to the composition of your skin. Underneath your dermis (upper layer of skin), you have a layer of fibrous connective tissue called superficial fascia. This connective tissue holds down fat into place. However, in many women, the superficial fascia is discontinuous and has “gaps” that allow fat to poke up onto the skin surface in clusters, creating the dimpled appearance associated with cellulite. Thus, there simply is no mechanism for magic cellulite potions to repair the gaps in connective tissue.
The only way to significantly diminish the appearance of cellulite is through dedicated exercise and proper nutrition. By stripping away fat to low levels, there won’t be much fat to press up on the skin. And by adding lean muscle, you’ll help to give the area an even tone and provide a supporting structure for a firm, smooth appearance. Unfortunately, there are no shortcuts.
Stay Fit!
Brad
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Uncategorized
July 24, 2009
The hot summer months are here and many of you are enjoying the ability to exercise out. But with the heat and humidity comes an increased risk for dehydration, which can potentially lead to serious side effects. Here are a few tips to ensure you stay hydrated:
Before Exercise: Consume generous amounts of fluid in the 24 hour pre-exercise period. Approximately 2 to 3 hours before training, drink about 2 to 3 cups of additional fluid.
During Exercise: Drink about 8 ounces of fluids every fifteen minutes regardless of thirst as the throat sensors are inhibited during exercise. Cool beverages are preferable as they help to increase absorption rate. For exercise lasting longer than one hour, sodium should be included in the drink to replace that which is lost through sweating. A small percentage of glucose (about 4 to 8%, as found in many sports drinks) can also be beneficial to maintain energy and increase the palatability of the fluid. Attempts should be made to conduct training when it is cooler (i.e. early in the morning, later in the evening) so that ambient temperature does not exceed body temperature.
After Exercise: Consume up to 150% of the weight lost during training. Fluids should contain some sodium to reduce dieresis and maintaining plasma osmolality, with the amount of sodium included dependent on sweat rate (i.e. higher sweat rates require greater sodium content of fluid).
Stay Fit!
Brad
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