SubscribeExercise Reduces Hunger in Lean Women NOT Obese Women
You'd think that the heavier a person is and the more exercise they do, the more benefits they receive-right? It doesn't seem that way. A new study has determined that exercise reduces hunger in lean women, but NOT obese women.
The participants-both lean and obese postmenopausal women-were fed "weight-maintenance" meals and exercised on a treadmill in the morning and afternoon at varying levels of intensity. After three days of testing, obese women said they were less hungry than lean women before meals, but experienced no appetite suppression during exercise. Wrap your mind around that!
"This [lack of appetite suppression] may promote greater food intake after exercise in obese women,"
Researchers point to the chemical leptin. Leptin is a hormone secreted by fat cells that regulates appetite. The fatter you are, the more fat cells you have, and the more leptin your body produces. That's why the blood taken from the obese women had much higher leptin levels than the blood taken from the lean women.
Now, during exercise the obese women only showed a reduction in leptin during moderate-intensity exercise, not high-intensity. So, if you're overweight and looking to jack up the incline on the treadmill. Try working up to it instead. In the long run it might make your diet a lot easier.
Very interesting. I know that for me personally, I am not hungry for a couple of hours after working out. I don't remember if it was always that way though...it's possible that I was hungry after exercising when I was obese. I don't think I did a whole lot of very intense exercise back then though...I started my exercise routine by walking a lot. Once I had lost a bit of weight, I started running.
The whole leptin theory is very interesting. I know a lot of people have heard of the experiment in which scientists knocked out the gene in mice that produces leptin. The mice that had no leptin got very obese because they had no appetite regulation. People figured that the magical answer to obesity was to give obese people leptin injections to help regulate their appetite. Turns out, as this study suggests, obese people produce a lot more leptin than thin people. There are theories that suggest that the leptin receptors are the problem in obese people...a condition similar to type 2 diabetes occurs where the body simply ignores the leptin in the body because there is so much of it being produced (which creates a similar condition to the mice that produced no leptin at all). So maybe thin people have a better leptin response than the obese people...very interesting. Maybe this is part of why Gary Taubes says that exercise is harmful to weight loss...because it makes you hungry. If you're obese that is.
ReplyIt is interesting... I would caution that it was a small study (n-20). I would like to see if they can duplicate this on a larger scale.
Also interesting is that leptin levels dropped only when during moderate intensity exercise. This WOULDN'T be a good thing, though as lower circulating leptin tends to STIMULATE weight gain. Spectra's understanding of the "resistance" of leptin receptors in the obese reflects my understanding.
That said, moving up gradually is always sensible - especially in the overweight. In fact, another recent study showed that lower intensity exercise benefited overweight teens moreso than high intensity exercise when it came to weight loss.
I would also be interested in more long-term results that translated into showing actual body fat/weight differences to see if the hunger factor would impede actual weight loss.
ReplyThis study did grab my attention, but I would think twice before recommending decreasing physical activity in the obese for fear of appetite stimulation. As Mike H. said this was a small study. What I would be very interested to see discussed is if regular physical activity has an impact on leptin resistance in the long term independent of weight loss.
I have found it true in the past with myself and with clients that physical activity did increase appetite initially, as is often the case early on when adding exercise, but it seems to balance out over time. Learning to control portions and exercise regularly is a process and everyone is different. I think people need to find what they are comfortable with and what works best for them in the long term.
ReplyI'm thinking that combining a higher intensity workout in obese people combined with a tightly regimented nutrition program would probably lead to a pretty fast weight loss. On The Biggest Loser, they start those people off on a killer workout routine and most of them DO admit they're "starving" during the first part of the show. I think it IS pretty important for obese people to start workouts slowly mostly so they don't get discouraged with the process and feel like throwing in the towel. I know I couldn't have started off running 3 miles a day when I first started exercising and if I had tried that, I would have done it exactly once and then I probably would have quit.
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