Last week the newswires lit up as consumers were warned, “People who eat out consume an average of about 200 calories more a day than when they cook at home.” At the same time the The National Restaurant Association reports and forecasts ever increasing sales and consumers spend about 47% of every food dollar away from home–a stark contrast to the 25% reported in the 1950′s.. We eat out a lot and we like it. Is obesity inevitable?
CALORIES AND FOOD QUALITY OF FAST FOOD VS SIT DOWN RESTAURANTS
The good news is that we are finally getting honest about the restaurant world. For over thirty years public health types have railed against fast food as the nemesis in our battle with the bulge. Today the advent of menu labelin means that sit down restaurants also get their fair share of scrutiny. In this study both quick service and sit down venues get skewered. We eat more at both locations than at home, and we eat more saturated fat, sugar and sodium as well:
- At a fast-food restaurant, there was a net increase of total energy intake (194.49 kcal), saturated fat (3.48 g), sugar (3.95 g) and sodium (296.38 mg)
- Eating at a full-service restaurant was also associated with an energy intake (205.21 kcal), and with higher intake of saturated fat (2.52 g) and sodium (451.06 mg)
And that’s when the reported findings of this study made me laugh (maybe cry?) out loud. Let me explain.
UNDERSTANDING PUBLIC HEALTH NUTRITION RESEARCH
The researchers, Lisa Powell from the School of Public Health at University of Chicago, and Dr. Nyugen of The American Cancer Society, looked at data collected from 12,000 adults interviewed in the 2003 National Health and Nutrition Examination Survey (NHANES). They assessed the results from a dietary tool known as a food frequency questionnaire (FFQ) that assesses how frequently you eat a food. Science Daily reports that the researchers went on to compare food intake consumed at home to food intake from fast-food and full-service restaurants on two successive days.
Most public health nutrition research are studies of large populations. By definition the study design is observational rather than interventional, so researchers use statistics to attempt to control for key variables that can influence an outcome. But we all know what is said about statistics. Even in the best of circumstances, this kind of research is limited to assessing the extent to which two things are related. The research cannot by definition determine cause or effect.
In the NHANES study large numbers of people are asked to recall what they ate years ago using a (FFQ). The researchers assess the results, and everyone wants to believe the findings–except we are relying on people remembering what they ate, and most of us are not reliable reporters.
PROBLEMS WITH RECALL
WHAT”S IN THE FOOD: Food can be complicated and people don’t always know what they are eating or what ingredients are used. If you are not familiar with shopping and you don’t prepare your own food, how do you begin to deconstruct a recipe or mixed meal?
HOW MUCH IS CONSUMED: Overweight people often get framed for under-reporting their food intake, but body size doesn’t really have anything to do with it. There is evidence that most of us under-estimate what we consume. In one seminal study at NYU by (then doctoral candidate) Lisa Young, even the dietetic students couldn’t reliably estimate portions sizes. Years ago I tested this theory at a conference with dietitians, asking them to estimate the weight of an apple, potato, muffin and cookie. I remember the answers ranged wildly (ie: the 3 ounce muffin estimates came in at less than 2 ounces and more than 5 ounces.) Even dietitians utterly failed to accurately size up portions.
WHAT IS REMEMBERED: Many of my clients struggle to tell me what they ate yesterday, so I am not surprised that sometimes people just make stuff up. I remember talking to nurses who participated in The Nurse’s Health Study who basically admitted getting so frustrated with the questionnaire that they just filled in whatever they thought they should. How would you answer, “For each food listed fill in the circle indicating how often on average you used the amount specified between 13 and 18 years of age.” Basically I am baffled that anyone reports results using such flawed data to the hundredths place with a straight face.
COUNTING CALORIES: MORE PHYSIOLOGY, LESS PHYSICS
Measuring the energy value of food is not the science everyone thinks it is. Since we don’t assess the the actual energy value of food using a metabolic model, it is likely we overestimate the energy in foods that don’t digest as completely. These include whole foods: vegetables, fruit, whole grains, beans, nuts and seeds. And we probably underestimate the metabolic mess resulting from a diet of highly refined starch, sugar and fat. Counting calories doesn’t begin to address what happens to calories once they are consumed. For too many of those highly processed calories are easily stored as fat.
Calorie counts on food labels can also be very misleading. The FDA allows a 20% margin of error in either direction to accommodate the variable nature of food. Sunlight, varietal strain, and a host of other factors influence the nutritional qualities of food, including the calorie yield. In effect, the calories listed on the nutrition label can over or underestimate by as much as 20% and still be printed as a “Nutrition Fact”. Has anyone else ever wondered if food manufacturers actively gamed the generous margin of error?
THE CALORIE BALANCE EQUATION IS FLAWED
We are foolish to continue to lean on the very flawed science of calculating calories and estimating calorie intake to tackle our metabolic challenges. Certainly calories count, but they are not the only thing that counts. A very good 2004 article published in Harvard Magazine outlines the many ways metabolism is much more complicated that a simple math problem. I am waiting for the day researchers stop assuming that calorie intake is the most critical factor determining weight status.
At the core of the problem, calorie counting misses the point. Ideally we eat with our bodies, not just with our brains. Calorie counting distracts us from what really matters: What mix of food takes our hunger away? Helps us feel satisfied? Provides us with the energy we need to tackle the tasks of the day? How much does flavor, texture, and presentation play a role? A preoccupation with counting calories limits the opportunity to truly nourish and nurture ourselves.
Ultimately each of us needs to figure out an approach to food that works. How will you step into eating better, not just less?