Americans’ obsession with weight control can lead them to embrace diet theories and convert too many of them into conventional wisdom. Alas, when medical researchers put widely accepted notions to scientific testing, they can evaporate faster than a rain drop on a hot summer sidewalk. That’s the potential fate of the idea that when people eat matters as much in weight control as what they consume.
This just isn’t so, according to “a rigorous one-year study in which people followed a low-calorie diet between the hours of 8 a.m. and 4 p.m. or consumed the same number of calories anytime during the day,” the New York Times reported, noting that so-called timed eating “has failed to find an effect.” The newspaper quoted Dr. Ethan Weiss, a diet researcher at the University of California, San Francisco, who reported this:
“There is no benefit to eating in a narrow window … These results indicate that caloric intake restriction explained most of the beneficial effects seen with the time-restricted eating regimen.”
As the newspaper reported:
“The study, published on [April 20] in the New England Journal of Medicine, was led by researchers at Southern Medical University in Guangzhou, China, and included 139 people with obesity. Women ate 1,200 to 1,500 calories a day, and men consumed 1,500 to 1,800 calories daily. To ensure compliance, participants were required to photograph every bit of food they ate and to keep food diaries. Both groups lost weight — an average of about 14 to 18 pounds — but there was no significant difference in the amounts of weight lost with either diet strategy. There also were no significant differences between the groups in measures of waist circumference, body fat and lean body mass. The scientists also found no differences in such risk factors as blood glucose levels, sensitivity to insulin, blood lipids, or blood pressure … The new study is not the first to test time-restricted eating, but previous studies often were smaller, of shorter duration and without control groups. That research tended to conclude that people lost weight by eating only during a limited period of time during the day.”
The latest study, though, has produced data so convincing that it even has persuaded author Weiss, whom the New York Times reported, “used to be a true believer in time-restricted eating and said that for seven years he had eaten only between noon and 8 p.m.” As the newspaper noted:
“In an interview, Dr. Weiss recalled he could hardly believe the results. He asked the statisticians to analyze the data four times, until they told him further work wouldn’t change the results. ‘I was a devotee,’ he said. ‘This was a hard thing to accept.’”
It is relatively rare for diet and nutrition experts to subject theories and approaches about eating to testing with tough standards. The work has its limits, as does all diet research involving humans due to the many “confounding” factors abounding — all study subjects’ bodily functions can’t, for example, be easily monitored 24/7, they can’t include a starved or deprived control group, and all the myriad, complex factors that affect health and nutrition can’t be controlled.
Further, as experts noted in discussing the time-restricted eating study, individuals respond in different ways to weight-control efforts, the New York Times reported:
“Dr. Christopher Gardner, director of nutrition studies at the Stanford Prevention Research Center, said he wouldn’t be surprised if time-restricted eating … worked on occasion. ‘Almost every type of diet out there works for some people,’ he said. ‘But the take-home supported by this new research is that when subjected to a properly designed and conducted study — scientific investigation — it is not any more helpful than simply reducing daily calorie intake for weight loss and health factors.’”
In my practice, I see the major harms that patients suffer while seeking medical services, and I have come to know all too well how they, and we all, struggle with the toll of excess weight. The federal Centers for Disease Control and Prevention estimates that 36% of adults and 17% of children in this country are obese, a chronic health bane that contributes to cancers, heart and lung diseases, diabetes, and more.
Big Food — corporate interests raking in huge profits, whether from fast food and chain restaurants or the making and processing of foods or the selling of sugary sodas and other drinks — aren’t keeping your health or mine as their top priority. Their efforts may be helping to make us poorer and sicker. We, instead, all need to eat sensibly and well but in moderation, while also exercising regularly.
That may sound like simple common sense. But, speaking of rigorous research, this approach to diet and nutrition is supported, for example, by an $8-million, year-long study conducted at Stanford University with more than 600 test subjects. The New York Times reported of this study, funded by the National Institutes of Health, the Nutrition Group, and others, that its findings would help debunk some long-held notions about dieting — and some diet fads. Here’s the core of the newly published work’s key findings, according to the newspaper:
“[P]eople who cut back on added sugar, refined grains and highly processed foods while concentrating on eating plenty of vegetables and whole foods — without worrying about counting calories or limiting portion sizes — lost significant amounts of weight over the course of a year. The strategy worked for people whether they followed diets that were mostly low in fat or mostly low in carbohydrates. And their success did not appear to be influenced by their genetics or their insulin-response to carbohydrates, a finding that casts doubt on the increasingly popular idea that different diets should be recommended to people based on their DNA makeup or on their tolerance for carbs or fat.”
That seems like sound guidance, and like the timed-eating information it is derived at least from research. We have much work to do to establish, in rigorous fashion, what works best for us with what we eat to stay healthy.