More reports from the Department of the Bleedin’ Obvious, my heart sisters. Last year, a group of 45 international nutrition scientists launched a campaign to end the use of one of their most commonly-used research tools: the self-reported food diary.(1) These scientists now claim that “dietary recall is skewed towards healthier behaviour.”
In plain English, it means this: people participating in nutrition studies lie to researchers about what they actually eat, preferring instead to enter foods into their daily food diary like “kale” and “quinoa” before submitting their self-reports.
And let’s face it, a person who has volunteered for a nutrition study may be too embarrassed to officially record for posterity something like: “I ate half a box of Turtles today just to get them out of the house.”* (And really, I can’t be the only woman to ever admit to this, can I?)
Trouble is, nutrition scientists are shocked by this research news because they’re thinking like nutrition scientists, not like Real Live People staring down an opened box of Turtles chocolates. I suspect that scientists have been asking the wrong people to fill out those self-reported food diaries.
What they need to do is to ask our girlfriends what we’ve been eating.
Our girlfriends know us and love us, and – most importantly! – have shared many a late-night wine-fueled confessional around our guilty pleasures. I can tell you precisely, for example, which of my friends during a stressful crisis is likely to dig into the Doritos, and which is heading straight for the Häagen-Dazs.
Meanwhile, we may officially self-report something like this in our official researchers’ food diary . . .
Day One, Breakfast: “3/4 c. Green Smoothie (organic kale, spinach, chia seeds, swiss chard, hemp hearts, dairy/gluten/soy-free protein powder, unsprayed grass clippings); three small raw almonds; one rice cracker; mint herbal tea made with filtered all-natural environmentally-sourced no-fat extra-lean fair-trade spring water.”
But if it were our girlfriends reading our food diaries instead of nutrition scientists who neither know us nor love us, they would grab the Sharpie pens right out of our chubby hands and replace that self-report with The Harsh Truth, something like this:
Day One, Breakfast: “She just scarfed down a double Eggs Florentine at brunch; chef’s special pesto roasted potatoes; one paper-thin wedge of the melon garnish; coffee – lots of coffee – with cream, not any of that lo-fat fake swill. Plus, she helped to polish off my leftover bacon (half a slice).”
Apparently, getting to that truth is critically important if you’re a nutrition scientist. This kind of dietary research seeks to answer questions like:
- Is a high-fat diet linked to breast cancer?
- Do fruit and vegetables protect against Alzheimer’s disease?
- Does a Mediterranean Diet help prevent heart disease?
For example, researchers studying obesity have intuitively assumed that people are obese because they consume too many calories. They’ve been puzzled, understandably, by paradoxical research findings that suggests obese people were actually eating fewer calories than people of normally weight.
But as the international nutrition study’s lead author Dr. David Allison explained:
“That was completely wrong. The correct answer is that, on average, obese people eat more than non-obese people. The wrong result was found and that confused the field for many years by relying on self-reporting.
“All of these studies, if they are based on self-reported estimates of calorie intake, really don’t contain scientifically meaningful information.”
Research results that don’t include accurate food diary data represent a serious problem. As one of the report’s authors warned, the flawed data collected in “thousands of scientific papers each year” could actually result in public health policies that are not science-based at all.
WHAT? Thousands of scientific papers resulting in public health decisions that are not science-based?
Yet this isn’t new news.
“A major problem in self-reported dietary studies is people who under-report their true habitual food intake.”
And even further back, a 1982 study published in the American Journal of Clinical Nutrition(3) showed that self-monitored records of research subjects’ food intake “may not be accurate”. In a study of overweight women (ranging in age from 24 to 53, mean age 44.6 years), scientists looked specifically at their food diaries and concluded:
“Judgments about calorie intake based on these estimates may not be accurate. Inaccuracies in the food records may render them non-representative of subject eating behaviour. “
So given the weight (no pun intended) of prior studies on precisely this problematic issue with self-reported dietary journals, why do nutrition scientists continue to rely on them?
Dr. John Ioannidis has suggested that even consistent results across studies don’t reflect accuracy in the link between eating _____ and developing _____, but rather “a literature that is written, peer reviewed and edited by fervent believers who will not accept any result other than what perpetuates their beliefs.”
“Much of the scientific community applauds us and says it’s a refreshing point of view. But as you might expect, some individuals who have based much of their research career on the use of these methods say we can’t abandon them because in part we don’t have anything better.”.
- help us see the big picture (not just individual food choices, but the cumulative effect over a whole day or a whole week)
- help us to identify patterns (when we write things down, we can start to see patterns develop for certain foods that might be contributing to a specific problem)
- help to kickstart us into action (even when we believe we’re eating healthy foods, we might be surprised by tracking the little snacks we enjoy here and there – and it’s also useful to count total servings of fruit and veggies per day)
- help us to feel more in control (writing things down helps the brain make sense of them, and helps us regain a sense of control over our eating habits)
- help us to eat more mindfully (when we write down all snacks, drinks, Turtles, or grazing throughout the day, we can become aware of how much mindless eating can happen).
Q: Have you ever fibbed while completing a self-reported food diary?
* Turtles: Heavenly morsels of pecans, caramel and chocolate; a Christmas tradition during my childhood. Sadly, I haven’t actually had a Turtle in many years, although I still have the occasional lovely nostalgic dream about eating one . . . ♥