# Does Time of Day Matter At All When You Eat, IRT Weight Loss/Gain? **URL:** \ **Category:** Factual Questions\ **Created:** [October 9, 2011, 1:53am UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048 "2011-10-09T01:53:47Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Covered\_In\_Bees](https://avatars.discourse-cdn.com/v4/letter/c/7ab992/32.png) [@Covered\_In\_Bees](https://boards.straightdope.com/u/Covered_In_Bees)\ **Post date:** [October 9, 2011, 1:53am UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048/1 "2011-10-09T01:53:47Z")
I call upon the collective Google-Fu powers of the SDMB to help me out. My Google-Fu, while it has grown stronger, still lacks the ability to find _good_ scientific articles/studies on various subjects. Can you guys help a fellow Doper out in finding some scientific journals/sites/publishings that say whether or not the time you day you eat matters at all to weight loss or gain? It is in the interest of fighting some ignorance for a few of my female friends. I am pretty sure it doesn’t matter when you eat, with regards to people’s metabolism and such things, probably read it right here on the Dope, but now I need some of those pesky citation thingies. Little help? ---
**Author:** ![Candyman74](https://avatars.discourse-cdn.com/v4/letter/c/ad7895/32.png) [@Candyman74](https://boards.straightdope.com/u/Candyman74)\ **Post date:** [October 9, 2011, 2:53am UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048/2 "2011-10-09T02:53:45Z")
I can’t help you with citations, but I will say that, as far as I know, any difference - if any - is so negligible as to be not worth considering. What matters is total calories in / calories out over a reasonably long period of time (weeks, not hours). ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [October 9, 2011, 12:06pm UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048/3 "2011-10-09T12:06:17Z")
You will find claims both ways. I cannot judge, but it is hard to see why the difference would be more than negligeable. ---
**Author:** ![Martin\_Hyde](https://avatars.discourse-cdn.com/v4/letter/m/47e85d/32.png) [@Martin\_Hyde](https://boards.straightdope.com/u/Martin_Hyde)\ **Post date:** [October 9, 2011, 3:27pm UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048/4 "2011-10-09T15:27:29Z")
From everything I’ve ever read (and I did days of research a few years ago when I went on a serious fat-loss program), physiologically it does not matter in any meaningful way in regard to weight loss. Psychologically there is good evidence it can be important. ---
**Author:** ![Imasquare](https://avatars.discourse-cdn.com/v4/letter/i/5f9b8f/32.png) [@Imasquare](https://boards.straightdope.com/u/Imasquare)\ **Post date:** [October 10, 2011, 12:52am UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048/5 "2011-10-10T00:52:07Z")
I just read something about this a couple of hours ago. It is an amazing coincidence is it not? [10 Stubborn Food Myths That Just Won’t Die, Debunked by Science](http://lifehacker.com/5847591/10-stubborn-food-myths-that-just-wont-die) See Myth 10: Don’t Eat After 6, 7, 8PM ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [October 10, 2011, 3:15am UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048/6 "2011-10-10T03:15:49Z")
Well actually that link ends up supporting the concept that when you meet matters. > [@](#): > > If a meal is skipped, the body begins a process of metabolic slowing commonly referred to as ‘starvation mode.'" [Eating early](http://www.jabfm.org/cgi/content/full/21/2/135) (breakfast) actually does help one lose weight: > [@](#): > > Those who skip breakfast have 4.5 times increased odds (95% CI, 1.6–12.9) for obesity compared with those who eat breakfast regularly (\>75% of days).48 Similarly, obesity is also associated with skipping breakfast 4 or more times weekly (odds ratio, 1.98; P \< .05).23 Furthermore, there may be advantages to eating breakfast in the context of attempting to lose weight.24 > > The exact mechanism of breakfast consumption and improved weight management is unknown. It has been shown that the number of eating episodes is inversely associated with the risk of obesity. Those who eat 4 or more times daily have a 45% lower risk of obesity compared with those who eat \<4 times a day.48 Paradoxically, studies show that the total energy intake can be greater in those who eat breakfast.48,49 The timing [does matter in animal models.](http://www.pnas.org/content/107/43/18664.short) > [@](#): > > Mice housed in either bright (LL) or dim (DM) LAN have significantly increased body mass and reduced glucose tolerance compared with mice in a standard (LD) light/dark cycle, **despite equivalent levels of caloric intake and total daily activity output**. Furthermore, the timing of food consumption by DM and LL mice differs from that in LD mice. Nocturnal rodents typically eat substantially more food at night; however, DM mice consume 55.5% of their food during the light phase, as compared with 36.5% in LD mice. Restricting food consumption to the active phase in DM mice prevents body mass gain. (Bolding mine.) [A similar article](http://groups.molbiosci.northwestern.edu/bass/publications/Obesity_2009.pdf). > [@](#): > > The present results show that simply modifying the time of feeding alone can greatly affect body temperature, satiety hormones and sleep could be contributing to the phenotype … the synchrony between circadian and metabolic processes plays an important role in the regulation of energy balance and body weight control. Importantly, this study is the first to show causal evidence that feeding at the “wrong” time can lead to weight gain. The present results indicate that a better understanding of the role of the circadian system in weight regulation could have important implications for combating the obesity epidemic facing the human population today. Once gained, losing body weight by controlling energy intake through dieting and/or energy expenditure has proven to be difficult over a prolonged period of time, making significant and sustained weight loss challenging (14). A preventive strategy based on behavior modification (e.g., the timing of food intake), possibly without a significant change in caloric intake or physical activity, could be a critical element needed to slow the ever-increasing incidence of obesity and associated cardiometabolic disorders facing the world today. The [BBC’s take](http://news.bbc.co.uk/2/hi/8234386.stm) on that study. > [@](#): > > Eating late at night adds weight … One group of mice ate at times when they would normally be asleep. They put on twice as much weight. > This was despite them doing the same level of activity, and eating the same amount of food, as the other mice. … “How or why a person gains weight is very complicated, but it is clearly not just calories in and calories out,” said Fred Turek, from the Northwestern’s Center for Sleep and Circadian Biology, where the research took place. > “Better timing of meals could be a critical element in slowing the ever-increasing incidence of obesity.” > Tam Fry, from the National Obesity Forum, agreed. He said: "It is groundbreaking. It really gets you thinking why this has not been done before. > “It could be very dramatic if it affects whether you are going to get fat or not.” While I would not say that it has been proven that in humans the same number of calories eaten late will cause more weight gain, I would say that dismissing it as a myth is premature. It seems more likely to be true than false. Sorry. ---
**Author:** ![elfkin477](https://avatars.discourse-cdn.com/v4/letter/e/a9a28c/32.png) [@elfkin477](https://boards.straightdope.com/u/elfkin477)\ **Post date:** [October 10, 2011, 3:27am UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048/7 "2011-10-10T03:27:06Z")
> [@DSeid](#): > > Well actually that link ends up supporting the concept that when you meet matters. > > [Eating early](http://www.jabfm.org/cgi/content/full/21/2/135) (breakfast) actually does help one lose weight: > The timing [does matter in animal models.](http://www.pnas.org/content/107/43/18664.short)(Bolding mine.) > > [A similar article](http://groups.molbiosci.northwestern.edu/bass/publications/Obesity_2009.pdf). > > The [BBC’s take](http://news.bbc.co.uk/2/hi/8234386.stm) on that study.While I would not say that it has been proven that in humans the same number of calories eaten late will cause more weight gain, I would say that dismissing it as a myth is premature. It seems more likely to be true than false. > > Sorry. The last article I read about human subjects said that eating at night only made people gain weight if the subjects were already obese at the start of the study. In people who weren’t obese, they found no changes related to eating times. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [October 10, 2011, 11:30am UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048/8 "2011-10-10T11:30:23Z")
I cannot find any such studies. What I find are lots that document obesity and metabolic syndrome occurring during shift workers, who work and eat at night, but an inability to separate out if that is because of an increase number of calories, or the effect of disordered sleep, or the time of day that eating occurs. ---
**Author:** ![bldysabba](https://avatars.discourse-cdn.com/v4/letter/b/ecccb3/32.png) [@bldysabba](https://boards.straightdope.com/u/bldysabba)\ **Post date:** [October 10, 2011, 12:23pm UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048/9 "2011-10-10T12:23:29Z")
> [@Covered\_In\_Bees](#): > > I call upon the collective Google-Fu powers of the SDMB to help me out. > > My Google-Fu, while it has grown stronger, still lacks the ability to find _good_ scientific articles/studies on various subjects. > > Can you guys help a fellow Doper out in finding some scientific journals/sites/publishings that say whether or not the time you day you eat matters at all to weight loss or gain? It is in the interest of fighting some ignorance for a few of my female friends. > > I am pretty sure it doesn’t matter when you eat, with regards to people’s metabolism and such things, probably read it right here on the Dope, but now I need some of those pesky citation thingies. > > Little help? When you eat, if viewed in conjunction with when you work out, may actually matter a fair bit. ---
**Author:** ![Covered\_In\_Bees](https://avatars.discourse-cdn.com/v4/letter/c/7ab992/32.png) [@Covered\_In\_Bees](https://boards.straightdope.com/u/Covered_In_Bees)\ **Post date:** [October 10, 2011, 6:12pm UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048/10 "2011-10-10T18:12:29Z")
Thanks for the responses everyone. If anyone else can find any such studies please by all means bring them to the attention of the thread. **Martin Hyde** : Do you happen to remember why psychological feelings/thoughts towards time of day when eating mattered? ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [October 10, 2011, 7:09pm UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048/11 "2011-10-10T19:09:32Z")
> [@bldysabba](#): > > When you eat, if viewed in conjunction with when you work out, may actually matter a fair bit. Probably [more than you’d ever want to know](http://jap.physiology.org/content/106/5/1692.full) about that. (Yes, protein in the soon, i.e. within 3 hours, preferably within 1 hour, after exercise period, or even a little bit before, seems to matter more than the same protein many more hours later.) ---
**Author:** ![Imasquare](https://avatars.discourse-cdn.com/v4/letter/i/5f9b8f/32.png) [@Imasquare](https://boards.straightdope.com/u/Imasquare)\ **Post date:** [October 10, 2011, 11:48pm UTC](https://boards.straightdope.com/t/does-time-of-day-matter-at-all-when-you-eat-irt-weight-loss-gain/599048/12 "2011-10-10T23:48:51Z")
> [@DSeid](#): > > The [BBC’s take](http://news.bbc.co.uk/2/hi/8234386.stm) on that study.While I would not say that it has been proven that in humans the same number of calories eaten late will cause more weight gain, I would say that dismissing it as a myth is premature. It seems more likely to be true than false. > > Sorry. Be sorry not - the fighting of ignorance is a noble cause after all. I’m not supporting the assertion that it is a myth - just sharing something I read earlier that day.