Science Fact: Slow food – it’s the cure for that logy holiday feeling, and for the fear of getting on the scale! Research consistently shows that eating more slowly helps you feel full with less food. That translates to a lighter, more energetic body and reduced mortality.
Definition of Slow Food
Before giving the science behind these assertions, for the purpose of this blog let’s define what slow food isn’t:
– Slow food is not the popular movement that protested the 1988 opening of a McDonald’s near the Spanish Steps in Rome.
– Slow food is not slow-cooked barbecue, as you might find at a Detroit restaurant, a Chicago catering company, and probably many other spots.
– And slow food is not what you prepare in a slow cooker, also known as a crock pot.
If our goal is weight control and overall health, slow food is “regular” healthy food, eaten slowly. Slow down and taste the roses!
A pre-Thanksgiving blog on this website gave guidance on the Holiday Diet, which included the advice to Slow Your Pace. Today we look at the science behind slow food as a dietary strategy. We’ll see the proof of the pudding, its surprising universality and practical tips.
Cause and Effect, versus Stuff That Happens Together
It’s been known for a long time that overweight people tend to consume food faster. Not only does a heavier person eat more calories (or ounces, or pints), but he eats more per minute as well.
Does that mean that eating fast causes you to become overweight? Not necessarily. My friend Charles South sent me this illustrative quote:
This would be like the governor of Iowa claiming his policies kept alligators out of the state. While it is true there are no alligators in Iowa, it has nothing to do with the governor!
Gaining weight is not quite like Iowa suffering invasion by a congregation of alligators (yes, that’s the term).
Here’s the point. Correlation means that A goes up and simultaneously B goes up. Causation means that A goes up and that causes B to go up. Correlation and Causation are not the same things. That’s where the science comes in.
A Slow Food Meta-Analysis
This year a group of eight researchers in UK, Netherlands and Switzerland published an important article. Dr Eric Robinson of the University of Liverpool was the lead author. The article was a meta-analysis addressing the Slow Food question: how does slow eating affect total food intake and feelings of hunger?
A meta-analysis is a systematic statistical analysis of multiple research studies. The individual studies may be quite different in design and objectives. However, the meta-analysis attempts to extract consistent results from all of them. It wants to determine exactly how well they confirm, or fail to confirm, each other’s results.
A meta-analysis is not simply a systematic review. Rather, it’s a mathematical procedure for combining evidence from many diverse sources.
The research team decided to scour the scientific literature for Causation, not Correlation. Specifically, they looked for studies that test whether you can cause people to eat less by forcing or encouraging them to eat more slowly. Using modern digital search plus old-fashioned word-of-mouth, they found 733 possible research articles. They screened the titles and abstracts to reduce this pile to a mere 73. However, most of those were eliminated because they did not attempt to change how fast people ate.
And the Results Were…
After all this filtering, a universe of more than 160 million articles shrank to just 22 research studies. We hope these will answer the question, did the governor’s skillful leadership keep the alligators out of Iowa? Well, not quite. What we really want to know, of course, is whether slow food leads to reduced food consumption. That’s important because a major cause of health problems is overweight.
Although 22 studies may not sound like much, they had a most impressive scope. In all, they tested more than 700 men and women of all ages from 13 to 65 years. The test subjects lived in eight countries: US, Netherlands, Sweden, China, Greece, Italy, Switzerland and UK. Most participants were of normal weight, but some studies also included overweight volunteers. With such a range of ages, nationalities and experimental design, it would be amazing if the results of such different studies were similar.
Two of the studies were published in 1980 and 1993, but all the others were recent, dating from 2007 to the present.
There was a great variety of test design. Often the same group of people would be tested on two separate occasions. However, sometimes a single group would be randomly divided to be tested either with slow food or the same food eaten more quickly.
How Researchers Got Volunteers to Adopt “Slow Food”
The different research groups used four general approaches to get their test subjects to try “slow food”:
– Verbal Instructions (4 studies)
Typical slow food instructions might be “chew each bite 30 seconds” or “chew each bite 35 times” or “chew thoroughly and swallow each bite before taking the next one.”
– Food Form (10 studies)
Slow food might have a hard rather than soft or mashed texture. Or, it might come in much smaller individual portions.
– Computer Feedback (8 studies)
A computerized device was used to measure the rate at which the test subject took food off his plate, by weighing the plate. For the slow food part of the test, the subject would be given feedback and instructions to slow his pace. All but one of these studies used a device called a Mandometer developed by Mando AB, a Swedish company. The company runs weight-loss clinics in Sweden, in New York City and in Melbourn, Australia using this invention. In appearance it looks like a doily that contains a scale, attached to a display device about four inches square.
– Food Delivery Rate (2 studies)
One of these studies had volunteers consume liquid yogurt using a straw (fast food case) or with a teaspoon from a bowl (slow food case). The other study used a food container that refilled at either a fast or a slow rate.
The researchers didn’t just measure how much food people ate when they ate quickly or slowly. 18 of the 22 studies also measured how hungry the test subjects felt, either during the test, just after it, or a few hours later.
Amazing Results from Slow Food
As previously pointed out, there were tremendous differences in these 22 different studies, in age, nationality and experimental design. Nevertheless, the meta-analysis found results that were remarkably consistent across all the research articles:
- Slow food means less total food. Slower eating leads to a significant reduction in food intake. This is true regardless of which approach is used to create “slow food.”
- Slow food does not leave you hungry. Volunteers who ate slowly, who therefore ate much less food, were no more hungry after eating or several hours later, than on other occasions when they ate more rapidly.
- What you know doesn’t affect the results. In seven of the twenty-two studies, the researchers used a “cover story” to conceal the goals of the research. In the other fifteen, the researchers told the volunteers the nature of the test. That didn’t affect the results. Eating slowly on purpose works just as well as when someone tricks you into eating slowly.
These are great results, but they are not the last word on dieting. After all, every time researchers study one question, the answers suggest still more areas to look at. Job security for the researchers? Yes, in the sense that science can never know everything, and the essence of scientific inquiry is to keep asking questions.
Here are several areas for further work that are suggested by this excellent meta-analysis:
Quantitative Differences Between Studies
The actual measured results varied tremendously in the different studies. The result “slow food equals less food consumption” was always true. Nevertheless, the actual amounts eaten and the rates of eating were quite different. For example, one study might show an 8% decrease in food consumed, while another might show a 30% reduction!
Other differences were evident when I looked at the seven studies with the largest number of participants, plus a more recent one not included in the meta-analysis. Individual studies suggested the following:
- Slow food as a diet strategy might work better for men than women.
- It might not work as well for obese people.
- And, it might work best with people who eat at a constant rate rather than those who start out quickly and then slow down.
Why all this variation in results? It could be due to individual differences, cultural or national differences, or the types of food offered to the volunteers.
Slow food seems to be just one facet of a larger research area involving how we decide how much to eat when we have food within reach. Much more work needs to be done to understand the psychology and physiology of eating, to help all of us achieve our desired weight.
How Does Slow Food Work?
The researchers proposed several mechanisms for why eating slowly might reduce total food consumption. Some of these will already be familiar to readers of this blog:
- Eating slowly gives your body the twenty minutes it needs for food in the stomach to signal the brain that it’s no longer so very hungry.
- Slow food gives you time to taste, smell and feel the food. Enjoying the healthy food may yield increased satisfaction with fewer calories.
- Smaller bites and more chewing may help signal your brain that you’ve had enough.
However, in general we can say that the scientific jury is still out concerning exactly how people decide when to stop eating. This is especially true for those who struggle with weight gain.
Slow Food in Real Life
No one yet knows whether it’s possible to translate these laboratory results into real life. We are surrounded by incentives to overeat: supersized portions that help create supersized people; restaurants designed to encourage fast eating so as to produce more revenue per seat; beautifully staged and photographed food.
What we would all like to know: can we as individuals do simple things, without looking like eccentrics or dorks, that will help us reign in our appetite for calories? It’s a question that’s especially timely with holiday feasts surrounding us late in the year.
As the Wodehouse character Jeeves often said, we must consider “the psychology of the individual.”
That is, research is clear that Slow Food definitely affects total calorie intake. However, everyone is different, and the best advice is to try different approaches and see what may work best for you. Conversation? Counting your chews? Starting your meal with foods that are firmer? Taking tiny bites?
Use your imagination, and perhaps you will find your magic bullet!
Here’s a bonus – a few personal stories! One of them may give you additional ideas.
Personal Story #1
One of my long-time friends, whom I shall call Carla, is a case history in slow food. She was raised to chew every mouthful thirty times. As an adult she may not be consciously counting her bites any more, yet she is one of the slowest eaters you might ever meet. When everyone else has wolfed down their lunch she will still be working on the starter salad. And she eats less total food than others around her at the restaurant table.
For Carla, slow food comes with a side effect: she can rarely pass a pastry or cookie shop without stopping for a morsel. Does this cause her weight to balloon? No, because fortunately she has another out-of-the ordinary habit: she walks five miles a day, year round!
Personal Story #2
This website, our Maui condo website and the websites I help manage for our condo association all use the hosting service GoDaddy.com. I’m personally a fan of GoDaddy: they are not the cheapest hosting service around, but they give excellent support, in fluent Arizona English. Also, they provide as much hand-holding as the client might require. They also have a great personal touch. Sometimes the GoDaddy support staff will take a few minutes to talk and put a human face on the large corporation.
I was talking with one such helpful tech and mentioned the blog that I was writing. He proceeded to tell me his own story about slow food.
The tech discovered, perhaps by accident, that making a point to converse while eating is not only a pleasant activity, but also reduces both the rate of eating and the total food consumption. He now makes a point of eating a bite of food, then putting down his fork and participating in the conversation before resuming eating.
His father has now adopted the same approach. The tech credits this approach to “slow food” with controlling his appetite and food intake, saving him not only poundage but also money.
Personal Story #3
At the University of Michigan in Ann Arbor I recently attended a performance of a Gilbert and Sullivan operetta that is not often performed: Ruddigore, or The Witch’s Curse. The heroine, a village maiden named Rose Maybud, slavishly follows the guidance of a book of etiquette, and accordingly she says to her aunt:
The man who bites his bread, or eats peas with a knife, I look upon as a lost creature.
Harry Benford’s Gilbert and Sullivan Lexicon explains:
In those days [the Victorian Age] a refined person would not be caught picking up a slice of bread and biting off a chunk. No. One was expected to break off a wee bit and pop it into one’s mouth in an inconspicuous manner.
My wife Nola’s parents were born in France, and Nola’s table manners reflect her French upbringing. She was taught that the proper way to eat bread and butter with a meal was to break off a small piece of bread; place it on the plate (not suspended in midair!) to butter it; and then eat it.
Both the Victorian approach and the modern French approach sound like slow food to me!
The US is #1 among nations in obesity but the Western European Continent ranges from #19 to #36 (France is #28). Therefore, perhaps it’s worth looking at table etiquette and customs as factors that pre-dispose Americans to put on more weight. (UK and Ireland are #8 and #9. Thus they don’t look like such good role models as the Continent.)
Have you ever purposely experimented with Slow Food, in the sense of pacing yourself to eat slowly? What results did you observe?
Drawing Credit: Cornucopia, from ClipartPanda.com