How we eat appears to influence how much we eat

Some individuals, hard as they try, may still fine it difficult to moderate the quantity of food they eat. At least one reason for this can be that they are eating foods that aren’t particularly satisfying. Two factors that affect the sating effects of food are the glycaemic index (the speed and extent to which a food releases sugar into the bloodstream) and it’s protein content. In short, the lower the glycaemic index and the higher the protein content, the more satisfying a food is. On the other hand, a diet made up of relatively high GI and low protein foods (a typically carbohydrate-rich diet) can be distinctly unsatisfying, and this can drive individuals to overeat.

It’s not just what we eat but how we eat it that can determine how satisfying food is to us. In 2007 I blogged about a study in which women were asked to eat a pasta-based meal under two distinct conditions. At one sitting, they were asked to take small bites and chew each one 15-20 times. At another sitting, they were asked to eat as quickly as possible. The women ate until they were satisfied. Compared to the faster-eaters, the women instructed to take their time and chew thoroughly consumed about 70 calories less. Not only that, but these women felt more satisfied immediately after the meal and an hour later.

On the back of this study I was interested to read about a similar piece of research that has recently been published on-line in the American Journal of Clinical Nutrition [1]. It took 22 individuals and measured their intake of a test food (semi-solid chocolate custard) under a number of different circumstances. For example, in one test, individuals were instructed to consume the custard using relatively small bites (5 grams of custard). At another time, they were instructed to take larger bites (15 grams). In both of these settings, test subjects were also asked to process the food in their mouths quickly (3 seconds before swallowing) and slowly (9 seconds). In all test settings, individuals were instructed to eat as much as they wanted and to stop when pleasantly satisfied.

One notable finding from this study was that less was eaten when the subjects took small bites compared to large bits. Average intake was about 100 calories less (about a 23 per cent calorie reduction).

Also, though, the longer the oral processing time, the less was eaten too (longer processing time was associated with a reduced intake in the order of 70 calories for small bite sizes and 50 calories for larger bite sizes).

What this study suggests that taking small bites and chewing them thoroughly (to increase oral processing time) may lead to a natural reduction in the amount of food consumed during a meal. It would be nice to see this study repeated with, not chocolate custard, but real food (e.g. meat and vegetables) to see how applicable these study results might be to the real world.

However, it is also worth bearing in mind that there is other evidence which supports the concept that what happens in the mouth can have a bearing on the satisfaction derived from food and how much of it is eaten. Research has found that eaten food is more satisfying than food just infused into the gut. Taking time to savour food properly might turn out to be quite powerful weapon in or efforts to prevent the overconsumption of food.

References:

1. Zijlstra N, et al. Effect of bite size and oral processing time of a semisolid food on satiation. Am J Clin Nutr 10th June 2009 [epub ahead of print publication]

9 Responses to How we eat appears to influence how much we eat

  1. Haarajot 19 June 2009 at 3:10 pm #

    This might be one of possible factors of eating more when stressed. I notice I eat more quickly and take larger bites in those circumstances.

  2. Chris P 19 June 2009 at 3:52 pm #

    Hi John, I would like to politely offer some thoughts for consideration.
    Paul McKennas book crossed my desk in the course of my interest and I read it without listening to the CD. The book is not so much about what to eat but about HOW to eat. In discussion with a friend a one liner was recounted to me. -”Have things really become so bad that people have to reminded how to eat?” Yep, that is the actuality.
    Although unspoken, Paul capitalises upon some important matters.
    There is a paradox that for some who attempt weight loss, either by calorie or food group restriction, there is a tendency to obsess about food and succumb to cravings. Another paradox is the belief that going longer between meals will help weight loss. Going longer between meals may result in a larger or rushed meal and this may be counter productive.
    My six penn’th is to suggest for discussion that hyperinsullinemia may be factorial in this.
    Both these paradoxes, if they are indeed valid submissions, have the the potential to be disruptive to the body. In the first instance, an individual may crave foods typically of high GI/GL, and in the second, the GL of the meal is greater by virtue of increased portion size. Both these effects raise the loading upon the body of blood glucose. Greater postprandrial loading; is that the expression? The concept of fast food or convenience food can be examined at a number of levels.
    Things have got so bad that some folks have to be (constantly) reminded how to eat and what to eat. Speaking more generally, we need for those with influence and/or responsibility to get to grips with the why.

  3. Dave 19 June 2009 at 7:52 pm #

    I’d ask the same question of this strategy as many other dietary interventions: what other animal needs to regulate how fast it eats? Does a lion count its bites of water buffalo?

    It takes time to generate the chemical signals of satiety, but the body has evolved to deal with this by making sure that you don’t get hungry until you’ve used up all the food you ate. Unless, that is, the energy regulation system isn’t working properly, either due to disease or because what we ate falls outside of the evolutionary norm. So I have no doubt that slowing intake of refined carbohydrates does a lot to improve satiety by reducing the associated insulin spike and thus making energy more available between meals. But, to me at least, it seems more sensible to just skip the spaghetti rather than count the number of times you chew it.

  4. Marilyn Finlay 19 June 2009 at 10:55 pm #

    Despite John Briffa’s constant exhortations to cut carbohydrate and up protein intake if we want to lose weight, I find that if I do this I a) lose weight extremely slowly and (b) feel very tired. Maybe for some people some carbohydrate (say wholemeal bread) is necessary even when trying to lose weight. I also feel hungry if I eat protein without carbohydrate.

  5. jenna 20 June 2009 at 3:50 am #

    I would have to agree with you Marilyn.
    Though I follow Dr Briffa’s blog due to my prolonged and increasing exasperation regarding my appetite/nutritional problems; I have had bulimia since 16 yrs of age. (I have seen psychologists, but am finding that my problems rather than psychological are most definitely related to what i eat) I can notice a huge difference depending on what I eat, but am finding that socially this is limiting, in that I am aware of how the food that I eat effects me deeply, but the people that I am with eat to simply enjoy and their health problems do not seem so apparent to them. Marilyn, I do suggest that you read Dr Briffa’s book, as his types, suggest differences in meal content, this regarding meat, fat, carbs etc. Personally, I have found this extremely helpful, and especially because it seems to echo what I feel instinctively about my relationship with food.

  6. Loz 24 June 2009 at 1:53 am #

    Dave has provided a useful common sense measure for us with the image of animals’ failure to count the number of times they chew. Meat-eating men seem to love references to Big Cats.
    He’s right: they do things naturally out there in the natural world…He’s right we should not obsess. We may however have to re-educate ourselves to rediscover what our bodies can tell us, to rediscover what the Big Cats never lost: receptivity to our own bodily signals, the freedom to explore what suits us best. Why is this necessary for the likes of myself, Marilyn and Jenna?
    …Big Cats do not eat in canteens. In fact they do not go to school, nor know the factory life that helped to determine state education’s traditions – both environments apt to teach us to deny our physical instincts. Nor do they have anything so mind-bendingly sick as the Holocaust or the Potato Famine somewhere deep in their family/community history. They were raised by a pride of unsophisticates with no access to the media nor all the pressures of human social existence, so they have no concept of the “eat to live? or live to eat?” challenge that the Italian & French traditionalist slowfooders pose to the Anglo-Saxon world. Live for all the pleasures that life affords, but particularly the basic one of knowing and responding to one’s own, very individual, physical reality…So remember to chat with your companions for 20 mins over a minimally processed appetizer before helping yourself to slightly less than you think you want of your main course, because there is always time to take more when you want it. I read once that it takes 20 mins for satiety to register. So let us take our time, and enjoy the human(e) company we can share our lives and our bread with.

  7. Trinkwasser 12 July 2009 at 8:09 pm #

    “t takes time to generate the chemical signals of satiety, but the body has evolved to deal with this by making sure that you don’t get hungry until you’ve used up all the food you ate. Unless, that is, the energy regulation system isn’t working properly, either due to disease or because what we ate falls outside of the evolutionary norm.”

    IMO that’s a large part of it, the Food Industry has discovered how to tap into the satiety signals and override them. Eating crap slowly is probably better than bolting it, but eating Real Food with an anatomically correct balance of nutrients works far more effectively.

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