The Problem With Promoting Smaller Serving Sizes

An emerging body of research is suggesting that we can make so me small changes that strongly influence us to eat less.

A review was recently published by the Cochrane group, lookingat 72 randomized controlled trials (RCTs) that were published through mid-2013. The research looks solid and offers some great advice on how to reduce portion sizes and overall food consumption.

First, I’ll review the findings and advice. Then, at the end of this article, I’ll tell you why this is problematic. Yes, solid research with great advice can still be problematic.

According to the review, people consistently ate more food when they were offered larger portion sizes, larger packaged portions, or larger tableware. They characterize the difference in consumption as small to moderate, but significant nonetheless at a caloric increase of 12% to 16%.

Here’s a little experiment conducted some years ago by Dr. James Painter & CBS News. It doesn’t seem at all far-fetched, and I’d be willing to bet these results would be repeated a majority of the time.

Not all that surprising, right?

Yet, look at what’s happened to portion sizes in the UK, since the 1950s:

Portion sizes 1950s vs Now

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And here’s a good picture of what’s been happening since the 90s:

Portion sizes 1990s vs Today

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Many suggestions have been aimed at industry to help get portion sizes under control. Unfortunately, they tend to run against the interests of the businesses themselves and would likely result in decreased revenues. For example, convenience stores lure in customers with gallon-sized cups of cheap, carbonated sugar-water, because those customers will purchase additional items, like snacks and gas, thereby increasing sales. Selling more for less is a tried and true business competition strategy.

As usual, change and experimentation at the personal level has far fewer barriers and dependencies.

What can we do ourselves to help reduce our portion sizes?

The best suggestions are to replace tableware with smaller plates, cups, glasses, and cutlery. Sure, you might eat additional servings, but most studies show that even if you do, you’ll still eat less overall.

OK, so what’s the problem with reducing portion sizes in order to reduce food consumption and ultimately reduce the size of the waistline?

Pure and simple, this advice assumes a calorie-dense, possibly nutrient-sparse diet.

Granted, this does describe the diets of most people in the industrialized world. However, it implicitly promotes continuing to eat the same foods, just less of them. It tells us Twinkies, Hot Pockets, chain pizza, and Coca-Cola should just be smaller.

Perhaps they should, but that’s not the only solution. It’s also unclear whether smaller portions would have lasting, long-term effects on weight control.

Another way to lose and maintain weight loss is to eat more. More volume, that is, while eating fewer calories.

You can eat quite a lot of food, if the food is calorically sparse. This is a natural consequence of eating whole foods, mostly plants. If you choose to eat this way, reducing your portion sizes would be unnecessary, and possibly a bad idea.

Your portion sizes can be intentionally large. You can eat your salads straight out of the mixing bowl. A serving of wild rice and beans can be substantial. A fruit salad doesn’t have to be tiny. A pile of mashed sweet potatoes can be eaten until your belly is full.

And filling the belly leads to satiety. As the stretch receptors in the stomach expand, they provide a satisfying sense of fullness that naturally tells us when to stop eating. Our gut bacteria help, too.

Better advice would be to take steps that help us eat smaller servings of the foods we want less of, but larger servings of the foods you want more of; larger salad bowls and smaller dessert plates.

But even there, one could drench a salad with horrible dressings, while someone else might have dark-chocolate strawberries for dessert. There’s no getting around the fact that food choices and portions require thought—and no rules will cover every possible case.

At the end of the day, what goes on your plate is more important than how much.

7 Replies to “The Problem With Promoting Smaller Serving Sizes”

    1. I suspect Hara Hachi Bu only works well when you eat and move like an Okinawan (i.e. whole foods and moderate physical activity). “Eighty-percent full” is still enough to gain weight on the Standard American Diet with its high calorie density. And this recent study indicates that sedentarism throws our satiety signals all out of whack, which would make identifying 80% difficult.

      Another interesting line of thinking is that gut bacteria tell us when we’re full. Apparently, it takes them about 20 minutes to produce a protein that sends satiety signals to our brains. Calorie dense foods make it easy to eat a lot of calories quickly, making it difficult to gauge how much we’ve eaten. So maybe the right advice for Americans is Eat at 80% Speed. Fewer calories in the first 20 minutes…

      Pretty cool how whole foods fix so many of these issues.

  1. I seem to be at odds here. I think we’ve talked before, but I’m not sure. I follow a high fiber diet (around 150 g/day, including supplemental fibers). I’ve cured myself of lots of diseases, and have maintained a weight loss of about 40 lbs for about 2 years. I’m a healthy weight.

    For about 30 years, I used to have weight issues. I followed the ideas of smaller portions. Or eating high volume, low calorie stuff to crowd out high density stuff. In my experience, it was gimmickry.

    My focus was on feeding my gut bugs. To what extent I did that vs something else, who knows. But I do know that I’m very different now. And the volume idea does not resonate with me.

    So take some recent lunches. I made baked potatoes. I love them cold with kimchi (don’t judge!). I eat two or three smallish potatoes with a cup or so of kimchi. That to me is a high volume, low density lunch. My wife recently bought me souse (a pickled head cheese). I think that is a high density food. I eat about 1 oz slice and combine with a leaf of mustard green. Nowhere near the volume of the potato lunch. But I’m just as full.

    I don’t know how to explain it, but my body knows the difference between high caloric density and low. Oddly, the 20 minute thing seems at odds too. IMAGINING eating the foods gives me different senses of fullness. I know in advance how much I will eat of something. Just by picturing it in my head. I very rarely deviate from what I picture in my head. 3 figs for dessert stays 3 figs.

    I think a healthy human gut should distinguish among foods with varying caloric density. And adjust so that the diet is healthy. I would’ve never thought this was possible before beginning my gut experiment.

    1. Hi, Wilbur. Would you say that eating for your gut results in eating a good amount of food with lower calorie density? I’m thinking that on the prebiotic side, fiber tends to bulk up foods while not adding to the calorie count. On the probiotic side, yogurt isn’t all that calorie dense compared to oils and junk foods. Vegetable probiotics tend to be low calorie, too. Fermented meats can be high calorie, though (salami,etc.).

      Another great way to eat for you gut is to avoid processed foods and preservative…which is another way of avoiding high-calorie, low-nutrient foods.

      I agree that your three-potato-and-kimchi lunch is high volume, low density. Sounds like something I’d eat. Even with smallish potatoes, I’m guessing you ate over a pound of potatoes with some fermented veg. Maybe the same calories total as a Big Mac, but double the weight, and lots more nutrition.

      There are a lot of triggers for satiety, and maybe they vary in strength by individual. For me, filling up is one of the best ways (stretch receptors). Raw vegetables and salads are great at this. soups, tomato sauce, whole grains, I’ve even been making some homemade whole-wheat pasta again, corn grits, beans, etc.

      For the most part, the high calorie, low nutrient foods are processed foods. There are very few in nature (honey and coconut are good examples…there just aren’t many).

      1. I don’t think so as a principle. Maybe on occasion. I take my fiber supplement drinks about 30 minutes after breakfast and dinner, so there’s no crowding out by them.

        A good example is peanuts. Thinking about them, I can somehow feel that they are nutrient dense, high calorie. If I were to eat them, I could only eat about 10 half-pieces (large Virginia type). That’s all I’d eat. I don’t need something to fill me up to prevent me from eating more.

        I’ve been like this for two years and I’m still amazed. I spent over 4 decades wondering why I couldn’t control my eating. I tried the small plate trick. I tried eating bulkier stuff. I think the problem is that, for me, is that it only works for the moment. Two hours later I’d be starving.

        Homestly, thinking about it more, I think I do eat more nutrient and calorie dense foods. Full fat cheese, fatty meats, dried figs, apricots, and plums. I eat stuff like mustard greens, broccolini, beans, etc. too, but not as fillers.

        Oh, I’d classify (good) honey as nutrient and calorie rich. Every once in a while I like a spoonful, but that would fill me up by itself! There’s definitely something other than stretch receptors working for me.

        1. There are multiple known satiety mechanisms, and stretch receptors are only one. For example, some satiety signals come from responses to macronutrients ( Some research indicates that protein is primary…we’ll keep on being hungry until we get adequate protein. And some of the most interesting research focuses on the role of gut bacteria. And, it’s safe to say there is some individual variance here, too.

          In the Paleo community, we don’t talk much about the stretch receptors—so it’s good for people to be aware of this mechanism, in case that’s the missing ingredient for them.

          1. I think that the gut bacteria are what did it for me. I don’t know if it’s a direct effect of targeting them with over 100 g/day of diversified prebiotics or an indirect effect of them having made me healthy.

            One thing that believe is true is that my gut bugs tell me what to eat. There’s been some research showing this on the negative side – eating lots of sugar feeds bacteria that use signaling to create cravings for more sugar.

            I believe that it works positively too. The foods I eat everyday are foods I crave. Not crave on the uncontrollable sense, but that I intensely want. I wanted mustard greens today for lunch, and had to make a special trip to get more. It sort of sucks because I make many special trips. Some things are near constant, like eggs, garlic, leeks, and very hot chile peppers. Others are infrequent, like liver and honey.

            This is pure freedom. I love passing on the bread handed out at restaurants because it holds no appeal to me, not because I’m using some sort of trick. I am very lucky!

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