Everyone in the world is quite literally on a diet, which consists of whatever they eat. A cow may eat grass or grain, but in either case the substance is its diet, and vice versa. In the laboratory sense, “diet” is value-neutral, with no judgment implied.
Then, there are special cases, like a diabetic diet or a celiac diet, intentional programs or regimes designed to eliminate any substance that will worsen the patient’s medical condition. But for everyday purposes, “diet” colloquially means “reducing diet.” For simplicity, most people say “diet” as shorthand for the concept of pursuing weight loss by consciously limiting caloric intake, which involves eating certain foods and, mainly, not eating other foods.
The premise behind the work of neuroscientist Sandra Aamodt is, “If diets worked, we’d all be thin by now,” so we know she means diet in the “Get a Bikini Body!” sense. Dr. Aamodt published the book Why Diets Make Us Fat, which explains the research behind the TEDGlobal talk she presented in June of 2013. It answers such questions as, “Why might one person lose 10 times as much weight as another person on the exact same diet?” (A sample is available of her reading of the audio version of the book.)
What got Aamodt fired up in the first place was the work of Dr. Jules Hirsch, whose 1995 study of caloric intake and energy expenditure reinforced, although it did not invent, the “set-point theory.” The Rockefeller University bio page holds this summary:
Both obese people and those who had never been obese reduced their energy expenditure when their weight was lower than normal, and burned calories faster when their weight was higher than normal.
The basic concept is, the set point mechanism can’t distinguish between a reducing diet and a legit survival-threatening famine situation, so it zealously defends its fat stores. The more strenuously a person tries to reach a weight that is below her or his predetermined “set point,” the harder the body will fight back. Thanks to the inexorable power of metabolic suppression, even a person who easily and successfully loses weight will eventually “plateau out.”
In fact, according to the studies on which Dr. Aamodt bases her theory, getting stuck at a certain weight is the best-case scenario. Because, says an article she wrote for The New York Times:
After about five years, 41 percent of dieters gain back more weight than they lost. Long-term studies show dieters are more likely than non-dieters to become obese over the next one to 15 years. That’s true in men and women, across ethnic groups, from childhood through middle age.
For one thing, concern about calorie restriction produces stress hormones, which increases abdominal fat, the dangerous kind. Surprisingly, there is evidence that exercise can reduce abdominal fat and produce health improvements, even when no measurable weight loss is attained. In other words, the scale is not the only measure of health — a finding that has greatly encouraged the Fat Acceptance movement.
Also, dieting teaches us to respond to external cues like clocks, calendars, scales, and calorie charts. But a brain that is trained to obey external signals is much more likely to respond to TV ads and billboards — which are, of course, full of messages that urge people to eat. What we need to do is focus on internal cues instead. Dr. Aamodt says:
I recommend mindful eating — paying attention to signals of hunger and fullness, without judgment, to relearn how to eat only as much as the brain’s weight-regulation system commands.
Your responses and feedback are welcome!
Source: “Obesity and Metabolism: Why Weight Loss Is Difficult to Sustain,” rucares.org, undated
Source: “Why You Can’t Lose Weight on a Diet,” NYTimes.com, 05/06/16
Photo credit: Dave Parker via Visualhunt.com/CC BY