How much we eat is a factor of many different factors including how hungry we are, how palatable food is, how much ‘reward’ we get from food and social setting. The body has complex systems in place that, when functioning well, help ensure that we eat enough food but not too much. Some of this control is ‘endocrinological’ (hormonal) in nature: hunger and appetite can be influenced by hormones that either stimulate or suppress appetite. Hunger and food intake can be influence by our neurology too. For example, the stomach contains nerves that are sensitive to stretch. These nerves send signals to the brain that tell it, essentially, how much food there is in the stomach.
Some interesting research published this week suggests that the sensitivity of ‘stretch receptors’ in the stomach varies according to the time of day [1]. Basically, at night, stretch receptors are more sensitive than during the day. In other words, during the evening and night, the stomach can feel fuller with the same amount of food had during the day. This mechanism would, in theory, help to moderate food intake before sleep.
There is a theory at least that this mechanism may help weight control. Research in animals shows that for a given number of calories, feeding at times during which the animals should be asleep can increase weight to a larger degree than if those calories are fed during wake-time. I not aware of similar evidence in humans, but the idea that excesses of food in the evening may be particularly ‘fattening’ is at least plausible. The fact that the body may put a natural brake on food intake in the evening may help.
However, I have to say, it seems many people seem to be well capable of over-riding this process. One of the most common cries I hear is of individuals saying that they eat ‘mountains of food’ late at night. Even though dinner may be imminent, some find themselves engaging in ‘fridge foraging’ or a ‘cupboard buffet’. Even after this, there can be a tendency for people to eat more than they feel they need, and perhaps not the best food either.
Time and again, people will express the opinion that they know this is not good for them, particularly when bedtime may be only a couple of hours away.
The cure for this phenomenon is usually quite simple, and requires individuals to be less hungry in the evening (for example when they return home from work). Some people have it their minds that ‘snacking’ between meals is to be avoided. I think if that ‘snack’ is a doughnut or half a pack of biscuits (cookies) then that’s probably true. However, the risk for some is that going from lunch to dinner without food can leave them utterly famished, inviting trouble.
In practical terms, the issue is usually easily dealt with by consuming a handful or two of nuts in the later afternoon and/or early evening. Coming home (or sitting in a restaurant) in a not particularly hungry state is what makes eating appropriate amounts of food in the evening much easier.
References:
1. Kentish SJ, et al. Circadian Variation in Gastric Vagal Afferent Mechanosensitivity. The Journal of Neuroscience, December 2013
Leptin take 4 hours to reach the brain. For proper weightmanagement you need to allow the brain to read the leptin.
Besides, the hormone program that ends with the important growth-hormone during deep sleep, starts with te release of prolactin. Insulin blocks the release of prolactin. So eating things in the evening with carbs in it will ruin the hormone program.
My simple rule : never eat 4 hours before sleep.
I whole heartedly agree that that is the best way to control weight and even loose those extra pounds. I find that a drink of warm lemon water helps to sate the appetite and avoiding carbs or sugary snacks is a must.
“For example, the stomach contains nerves that are sensitive to stretch. These nerves send signals to the brain that tell it, essentially, how much food there is in the stomach.”
Yes, Dr Briffa, and people who have restored some semblance of portion control to what they eat often report that they sense that “their stomach has shrunk” ?
Now you beg the question; has their stomach actually shrunk or have they become more sensitive to ‘stretch’ neurologically speaking, and/or less comfortable with having a full or even distended stomach?
Provided that levels of insulin have been permitted to stabilise and fall, I would say, I find an empty stomach alone doesn’t give rise to the sensations hunger or the compulsion to eat, and this is because my body is presently such that I can afford to spend some time running upon my own stash of energy sequestered as body-fat. With insulin levels low lipolysis and ketosis (burning body-fats) can take care of my energy needs, I think. I feel better, feel more energised, feel less compulsion to snack, and find the results reflected upon the scales.
It is a long term trend, the goal being 80-85 kilos, currently 95 or thereabouts, and down from an all-time high of 111.
Fats are good, carbs are OK, but being significantly overweight is just a very plain signal that the carbs have featured too greatly in the diet, in my (unqualified) view.
Enough sleep makes a great deal of difference, too. Fatigue destabilises levels of insulin, I have read and I have found in accord, and greatly encourages snacking.
Let’s put the low-fat lobby out of business, I say.
Dear Dr
On a related point, I wonder if there is any research, or even thought, to their being some evolutionary adaption, a gustatory/digestion indicator, whereby the very act of sitting down signals that it is a good time to eat? It follows that standing, walking, being active as our prehistoric, hunter/gatherer ancestors would have been for most of their time was a behaviour that signalled somewhat suppressed appetite (via the gustatory/digestion loop) and hence preserving resources to enable the procurement of food but not its consumption.
Sorry if this is a ramble but I think you’ll get what I mean. Does the very act of sitting down trigger a primitive response to eat?
Kindest regards.
I find brushing my teeth not too long after my evening meal helps me!
In my more advanced years I find that if I eat carbohydrates late in the evening that frequently on retiring I suffer from indigestion which disturbs sleep yet, interestingly, this does not occur if the late bite is protein or fat. I also find that retiring on an empty stomach allows me to sleep more soundly; it seems that the stomach, and presumably most organs of the body, enjoy a rest.
“I wonder if there is any research, or even thought, to their being some evolutionary adaption, a gustatory/digestion indicator, whereby the very act of sitting down signals that it is a good time to eat?”
That’s a curious thought, but if you find yourself watching TV of an evening, and then while so doing you get up and walk to the fridge or cookie jar in search of a nibble, it isn’t really a conscious decision that has you do so. It’s more to do with hormones commanding you, or commanding your thoughts/actions.
According to some authors the best thing to do would be to go to bed. They say sitting up late in artificial light allied with not getting enough sleep (they recommend at least 9.5 hours) is something that has levels of the hormone cortisol remain unnaturally high. Cortisol sits at the top of a pyramid and can cascade influence upon other hormones including insulin.
It’s slightly catch 22. Cortisol may keep you up, but it’s staying up that keeps cortisol high of an evening. Get enough sleep, the argument goes, cortisol drops to base-line levels and levels and levels cycle in the way nature intended. Natural order is restored.
Exposure to light (not all of which is natural) married with sleep shortage is something that can encourage over-eating and carb craving, so they say, and it does match my experience.
If anything the modern human is too enterprising for too many hours of the day. And actually, in contemporary subsistence, hunter-gather, societies they can provision their needs, generally with around 3-4 hours of enterprising activities per day. Paradoxically they may actually spend more time at rest (sitting, chilling, laughing, siesta-ing) than we do.
How can the paradox be explained?
If they don’t have to compete for a share of a resource with which to buy the essentials that meet their needs they do not suffer the same dispossession of their time that we ‘civilised’ people do. Without TV and advertising they are content with their lot, and happier for it.
Cave art never had ‘sponsored by Cadburys’ (or Budvar) written alongside it, did it?
If people eat a large and fast evening meal more insulin is released and glucose is removed too quickly leading to blood sugar crash and carvings. AlsoI think evening eating also has a bearing on serotonin – melatonin. Eating some wholegrains near to bedtime promote sleepiness and converts short term serotonin to melatonin – aiding sleep,and prevent s
blood sugar dips around 3 am. Often people who are low in short chain fatty acids (provided from fibre) cannot sustain a night time fast without blood sugar levels dropping.
@ Zarayna Pradya: that is an interesting thought.
I first visited the USA in 1977 and one (among) many things I noticed that was different to the UK was how many people walked around drinking and eating, even on public transport, outside meal times.
At that time in the UK, apart from maybe ice cream, I don’t think anyone ate and drank on the move. Drinking from bottles was considered bad manners and ring pull cans of ‘pop’ was a novelty, walking round with a polyfoam cup of tea or coffee was unlikely.
This greatly reduced snacking time.
It is of course now commonplace to see people in the street, on buses and trains, almost continually feeding their face.
Given what you say, I wonder how much this mobile grazing contributes to people getting more weighty, given it increases the time people engage in eating?
Perhaps Dr B has a view.
I think many people are just get used to eat later in the evening. Probably, giving yourself a promise(or an order) to strictly avoid such behavior for three weeks may help to form a new habit. I guess it is easier to be harder on yourself during shorter period of time.
I was raised by a mother who did not allow family members to eat at night, so I am uncomfortable to eat close to a bed time as a result. It didn’t keep me thin, but it is possible that following principles of a healthy life style (always cooking my food and doing exercises) saved me from being obese.
Grazing was my main problem, so I do think that eating constantly is one of main reasons why Western population is getting fatter. When I was little, children were not allowed to eat between meals (to preserve their appetite) and to choose what to eat.
Evening eating has more to do with your personality and evening activity than anything else. Or the correlation coefficient with personality and activity is high, but what do I know.
To me it still feels impolite or wrong to eat or drink while walking. I’m from the UK and I’m getting on a bit! LOL. I wouldn’t eat on a bus or train unless I really had to either
“Some interesting research published this week suggests that the sensitivity of ‘stretch receptors’ in the stomach varies according to the time of day [1]. Basically, at night, stretch receptors are more sensitive than during the day. In other words, during the evening and night, the stomach can feel fuller with the same amount of food had during the day.”
This was very interesting to me because I had bariatric surgery in 2009 and now only have a very small “sleeve” stomach. I have commented to doctors in the past how it seems I can eat a very good amount of food in the morning but not nearly as much in the evening, and if I try to, I am much more inclined to vomit, which has never happened in the morning. The doctors didn’t seem to convinced but now I have the evidence why, so many thanks Dr Briffa!
I used to eat more-or-less non-stop from 4 pm, when I got home from work, to about 7 pm, when dinner was ready (this was after a breakfast at 5:30 am and lunch at 12:00 pm). I would no longer be hungry by 7 pm, but then felt guilty about the junk consumed in the previous 3 hours and ate dinner just so that I could say I ate something “healthy”.
So I changed my habits. I now eat dinner by 4:30 at the latest (when I am hungry), even if the rest of the family only eat later, and then I’m fine for the rest of the evening, needing no further snacks to “keep me going”. One should just learn to listen to one’s body and not try to change it’s rhythm by forcing it to eat “later” or “earlier” than what comes naturally. My body’s daily rhythm may be a bit earlier than most people’s daily rhythms (many people can’t eat at 5:30 am, but I’m wide awake and hungry by then — about an hour and a half after waking up naturally) and so I need to eat dinner early as well (and go to sleep earlier than most, 9 pm 🙂 ).
I am not sure that is so relevant.
I can eat a 600g steak, four whole eggs and 50g butter and be very satisfied but not overly full or I can eat 200g of fatty pork crackle and feel sick at which point the though of any other food intake repulses me.
Clearly there are some other factors going on, stretch may of course contribute.
Snacking is largely habit, and for many people it is a major factor in whether they can lose significant amounts of weight. A planned meal like afternoon tea with veggies, a few nuts, cheese, etc, is not the same as most snacking. I found I had frequent stalls as long as I snacked. I venture that most people snacking do so in an unregulated fashion, which can result in hundreds more calories consumed. I have found I feel better eating a bit earlier around 6-7pm, than later. Also, making a cup of hot herb tea or other non-caffeinated beverage is a good option instead of snacks during the day or night.