22 April 2012
Beyond calories in, calories out -- look to the Amish
What is wrong with "eat less, move more"? Most of us are familiar with this mantra as weight-loss advice. However, a new consensus statement from the American Society for Nutrition (ASN) and the International Life Sciences Institute (ILSI) contends that this energy-in-energy-out framework isn't really so simple.
The problem lies in that consuming fewer calories and burning more through physical activity doesn’t always translate well to weight management. That is not to say that the framework of energy balance—negative energy balance for weight loss; positive energy balance for weight—is wrong. At some level, it’s right; however, several factors come into the equation.
During a Saturday morning session of Experimental Biology (#EB2012) in San Diego, Calif., researchers discussed the topic of this complexity and promoting a new paradigm on energy balance.
Energy balance is not just about addition of diet and exercise; each affects the other, so that changing one changes the others, explained Jim Hill, professor of pediatrics and medicine at the University of Colorado School of Medicine, Denver, and new recipient of the W.O. Atwater Lectureship awarded by the American Society for Nutrition.
What must be appreciated is the body's system of active regulation, he said.
"It's not just a little man in your head that," he said, adding that the body may rely on a 'set point' or 'settling point' type of system that attempts to balance energy, energy stores, glucose, glycogen, fat stores, and temperature.
"You might argue that up to the 1970s, the system worked pretty well," Hill said. "This whole system is based on inherited factors. If you look at what’s really changed since the 70s, it's really the environmental factors. We don't have to hunt and kill our food anymore. We go to the supermarket and fill our carts. We also sit in some form of fashion every day."
Obesity, a problem of overwhelmed "active regulation"
Most of these environmental influences are designed to increase energy intake. It becomes more difficult to avoid overeating and underactivity. These influences, summed up, overwhelm active regulation and the body’s energy balance system. Then the body's physiology adjusts.
Are there things in the food supply that cause to eat more? Are they influences that affect our brains and nervous system? Hill said that however they may affect us, it is still through energy balance. He said he "laughs every time" he sees studies questioning whether the rise of obesity epidemic is related to energy intake or expenditure.
"Diet and physical activity interact," he said. "Please don't ask if it's diet or physical activity. The answer is 'yes'."
What wrong with diets? No matter which diet, Hill said, the results are always the same: Body weight may increase, may not change, or may decrease. The inconsistent outcomes may be because of poor compliance, physical activity, metabolic rate differences, or food intake adjustments. Eventually, what goes wrong is that environment affects behavior so strongly that over time that people are gaining a little weight. They don’t gain a lot, but they gain about a pound or two a year with some push back from their active regulation systems.
One way to combat the obesity epidemic is by encouraging an environment more like that of a half a century ago, Hill said. How the old order Amish live today is a good example.
"The Amish walk 18 thousand steps a day. They don’t have spandex or a gym membership. That explains about 400 to 600 calories a day. A typical person in the U.S. walks only five to six thousand steps a day," Hill said.
Hill suggests preventing weight gain with small steps—or, more specifically, 2 thousand steps daily.
"We have a poor ability to maintain weight loss, but we have a better ability to prevent weight loss,” he said. “This is why we started a movement to move. Two-thousand steps a day is not going to create weight loss, but might prevent weight gain."
What role can small changes play in an environment where we need bigger systemic changes? Hill argues that it will "set the table" for bigger change. Another factor may be that it may help to improve performance or "reset" active regulation.
"Our biology works best at high levels of physical activity. Obesity is in the 'unregulated zone.' When physical activity increases, you enter 'regulated zone'. Physical activity may help the 'regulatory system' work better."
Until bigger changes can be created in the environment, Hill is a fan of "stealth health" strategies for reducing obesity. That is, finding ways of encouraging better energy in, energy out balance without the public noticing.
For example, Hill explains, at Disney parks and at Starbucks, drinks are now made with low-fat milk. Does anyone notice the difference? What about portion sizes? Would anyone notice a 5 percent reduction at restaurants?
Another idea Hill proposed was that of regulation of school drop offs—so that they would be 500 steps away from the school. Would it be so far that the children would notice a difference?
The implementation of these "stealth health" strategies would increase physical activity and reduce overeating. Combined with teaching children energy balance skills, it could reduce childhood and overall obesity.
What also may be important is to combine both diet and physical activity guidelines for society? But how can this be achieved when studies show that energy balance is such a dynamic versus static process?
Learn more about the questions raised about energy balance at Experimental Biology from the American Society for Nutrition’s cover page story in Nutrition Notes Daily.