RMR slows on eating frequently

yarwell

A study of healthy lean young men fed the same food in either 3 meals or 14 "meals" per day found that their Resting Metabolic Rate reduced by ~120 calories a day and ~15% less protein was oxidised (used as fuel) on the higher frequency eating pattern.

Discussed at http://www.drbriffa.com/2012/08/31/how-often-should-we-eat-2/
Study published at http://www.plosone.org/article/info:doi/10.1371/journal.pone.0038632

nxd10

I teach statistics. Those results are not particularly impressive - they ran 11 tests and got two statistically significant differences in the groups of the .05 level - one on protein oxidation and one on resting metabolism. There are only 12 lean young men in the study. All of which suggests that these findings are interesting and suggestive, but not definitive.

More importantly, at least from the abstract, they say that fat metabolism didn't differ in the two groups - so it didn't help one way or another in losing adipose tissue.

They did find that men who eat less frequently were LESS HUNGRY. And they thought that was the most important thing long term for maintaining a diet that would keep you slim.

Results
Glucose and insulin profiles showed greater fluctuations, but a lower AUC of glucose in the LFr diet compared with the HFr diet. No differences between the frequency diets were observed on fat and carbohydrate oxidation. Though, protein oxidation and RMR (in this case SMR + DIT) were significantly increased in the LFr diet compared with the HFr diet. The LFr diet increased satiety and reduced hunger ratings compared with the HFr diet during the day.

Conclusion
The higher rise and subsequently fall of insulin in the LFr diet did not lead to a higher fat oxidation as hypothesized. The LFr diet decreased glucose levels throughout the day (AUC) indicating glycemic improvements. RMR and appetite control increased in the LFr diet, which can be relevant for body weight control on the long term.

azalais7

Who eats 14 "meals" a day? The study might be more useful if it had looked at eating 5-6 a day, as that's a range I see recommended often when more frequent but smaller meals are advised.

yarwell

Who eats 14 "meals" a day? The study might be more useful if it had looked at eating 5-6 a day, as that's a range I see recommended often when more frequent but smaller meals are advised.

In testing out a hypothesis it's not unreasonable to go to an extreme - if it doesn't work at the extreme it isn't likely to work in the middle ground and you stand a better chance of finding something statistically significant.

As for the results "not being impressive" they were looking to test something, and no difference at all would be a valid answer wouldn't it ?

I didn't expect that the lower frequency eaters would be less hungry.

Hendrix7

I assume the intent was to disprove the myth that higher meal frequency increases rmr, more than to show lower lower frequency has some huge advantage and it was successful in doing that.

Would be interesting to see if the same result was acheived with a more realistic comparison of 3 meals and 5/6 meals.

wild_wild_life

Interesting, thanks for posting. On a somewhat related tangent, I just came across this article:

http://www.biolayne.com/nutrition/carbs-at-night-fat-loss-killer-or-imaginary-boogeyman/

He discusses a couple of interesting studies including one that compared a group eating carbs throughout the day vs mainly at night -- biomarkers and satiety were improved in those eating them at night, supposedly due to the body's adaptation to gluconeogenesis vs regular intake of glucose and accompanying insulin release.

This is the study, I can only access the abstract.

http://www.nature.com/oby/journal/v19/n10/full/oby201148a.html

The article also discusses studies showing that in lean individuals, RMR while sleeping (SMR) is higher than RMR while resting, which I thought was interesting.

nxd10

Who eats 14 "meals" a day? The study might be more useful if it had looked at eating 5-6 a day, as that's a range I see recommended often when more frequent but smaller meals are advised.

In testing out a hypothesis it's not unreasonable to go to an extreme - if it doesn't work at the extreme it isn't likely to work in the middle ground and you stand a better chance of finding something statistically significant.

As for the results "not being impressive" they were looking to test something, and no difference at all would be a valid answer wouldn't it ?

I didn't expect that the lower frequency eaters would be less hungry.

Is it your study? If so, I'm sorry, that was blunt of me to state it the way I did.

No difference with a small sample could easily be due to lack of statistical power if you have a small effect. It is harder to prove no difference than to get good evidence of a difference.

The findings that people were less hungry when they eat less often was not only really interesting, but actually contrary to the idea that grazing throughout the day (which is what I think the 14 meal group really models). It's also really interesting in that if you look at insulin spikes and regulation of adipose deposition, you'd think it would be the other way around. They got a pretty big effect. With a larger sample, it would be interesting to see if that partly has to do with people's normal patterning of eating. They only follow the people for 3 days (which is good for measurement, but a short time). Insulin secretion is a learned, as well as prompted, behavior. So thinking about food because it's lunchtime causes insulin secretion.

paint_it_black

Who eats 14 "meals" a day? The study might be more useful if it had looked at eating 5-6 a day, as that's a range I see recommended often when more frequent but smaller meals are advised.

A much advertised and publisised 'babyfood diet' which involves eating 1 small portion of babyfood 15 times per day. Supposedly Lady Gaga and Cherl whatever her name is this week follow this diet. Ah the knowledge imported from airhead yoyo dieting rl friends finally has value ;-)

AlabasterVerve

I missed this one. Maybe that's part of the reason low carb eating helps to control my appetite -- I go for extended periods of time not eating because I'm not hungry and perhaps the "not hungry" bit gets reinforced because I'm not snacking. Interesting stuff, thanks for posting, yarwell.