After all those years of not eating red meat and cutting back on the mayonnaise, science now tells us it’s carbs, not fat, making Americans overweight.  This interesting infographic designed by Column Five Media for Massive Health describes in depth the way in which carbohydrates make the body store fat.

“One of the reasons we did this infographic is because we are finding through the data we are collecting via The Eatery that people are not very good at judging the health of certain foods,” says Andrew J. Rosenthal of Massive Heath.  “One of our users was starting off each morning with a Jamba Juice fruit smoothie, thinking it was a really healthy substitute for breakfast.   Every day as he used The Eatery, he got feedback that his smoothie was not nearly as healthy as he had rated it.  He had no idea how high the sugar and carb content was.  We’ve heard about loads of “ah-ha!” moments like this particularly about carbs, when users of The Eatery learn, through a tight feedback loop, that their decisions aren’t nearly as healthy as they thought.”

[Sign up for Food+Tech Connect Bytes to have stories like this one come directly to your inbox.]

About Beth Hoffman: Beth Hoffman is the Managing Editor at Food+Tech Connect. She has reported on food and agriculture for ten years, airing on NPR, The World, Latino USA, Living on Earth, KUER and KALW , and studied the food system in depth as a fellow and co-lecturer in the Africa Reporting Project at UC Berkeley’s School of Journalism. Hoffman competed a year long documentary project cooking with immigrant women in their homes, has traveled to India, Uganda and Ethiopia to report on rice production and chicken farming, and did a multipart series for KUER on the artistic, cultural and environmental connections we have to food. In addition to spending many hours on-farm in Utah, California and abroad, Hoffman also married into an Iowa farm family and is currently working with her husband to slowly convert the land into a sustainable orchard and hog farm. She currently lives in Albany, California. Hoffman’s previous work can be found on her website at bethaudio.com.

September 1, 2011

Motor neurons die, particularly from age 60 onward. This causes connections between muscle fibers to wither — and that, in turn, eventually leads to loss and shrinking of muscle fibers. As a result, muscles get smaller and a person gets weaker, says Sandra Hunter, an associate professor of exercise science at Marquette University in Milwaukee. “Physical activity can offset some of that,” she says. “But there is this biological aging process going on — the neurons will die regardless of how fit you are.”

Beginning in the late 30s, maximal oxygen consumption, or VO2 max, decreases at a rate of at least 10% per decade, or about 1% per year, in most people other than highly trained athletes. VO2 max is dependent on heart rate, which decreases by about 5 to 10 beats per minute per decade. This reduction in aerobic capacity is one of the reasons for a decline in endurance performance with age. “You can’t send as much blood and oxygen to the working muscles, and the pace slows down,” says Jason Karp, a running coach based in San Diego. Hard aerobic training can offset the decline in VO2 max — up to a point.

With age, large, elastic arteries including the aorta (which shuttles blood from the heart) and the carotid artery (which feeds blood to the brain) get stiffer. As a result, blood pressure rises and the heart has to work that much harder. In addition, the inner lining of arteries, called the vascular endothelium, loses certain functions: Signals that normally open the arteries and increase blood flow or narrow the arteries to reduce blood flow are not operating properly. As a result, the artery remains in a relatively narrow state, contributing to cardiovascular disease, says Douglas Seals, a physiologist at the University of Colorado at Boulder. Beyond the health ramifications, he adds, “if the arteries do not vasodilate robustly in response to these signals, then they cannot increase blood flow appropriately to meet the demands of increased energy metabolism of the exercising muscles — and performance will be limited.”

Wear and tear builds up on the joints. Connective tissue becomes less elastic, and lubricating fluids decline, making aging athletes more injury-prone. Cross-training — doing a mix of high- and low-impact exercises such as weight training, yoga and cycling — works different muscle groups and can reduce the risk of orthopedic injuries from overuse, says Michael Joyner, a professor of anesthesiology and an exercise researcher at the Mayo Clinic in Rochester, Minn. And (though research is limited) studies suggest that a lifelong exercise habit helps keep joints intact. In part, this could be because activity improves blood flow and other regenerative pathways and may activate stem cells that help the body repair itself, Joyner says.

How much can exercise slow down the ravages of aging? Potentially a lot.

It will partially, but not completely, prevent arterial stiffening with age and completely prevent the dysfunction of the arterial lining that develops with age, Seals says. “Exercise, it turns out, is probably as powerful as any other kind of prevention strategy or treatment that has been assessed so far.”

Scientists are also encouraged by studies on mice with a certain genetic mutation that makes them age prematurely — complete with graying and thinning fur, cataracts, hearing loss, smaller brains, enlarged hearts, anemia and thin and weak muscles — hallmark symptoms of growing older. To test whether it was possible to slow or reverse the process in these mice, a team led by Dr. Mark Tarnopolsky, a professor of pediatrics and medicine at McMaster University in Ontario, Canada, had the rodents exercise on treadmills three times a week from the age of 3 months to 8 months (about ages 20 to 55 in human terms).

In a 2011 study in the journal Proceedings of the National Academies of Sciences, the researchers showed that the exercise prevented many of the physiological symptoms of aging as well as premature death in the mice — to the point where they were indistinguishable from non-genetically altered mice.

“We protected not just the muscles — which people conceptually would say, ‘Well, yeah, it makes sense that if you run, your muscles will be protected’ — but even their cataracts, their kidneys, their gonads,” Tarnopolsky says.

Similar results can be seen in humans. For 21 years, researchers at Stanford University have studied the effects of consistent exercise on 284 runners 50 and older. In a 2002 article in the Archives of Internal Medicine, they reported that — 13 years into the study — a control group of 156 similar people who exercised much less on the whole than the runners had a 3.3 times higher death rate than runners as well as higher rates of disabilities.

In a 2008 study in the same journal, they reported that after 19 years, 15% of runners had died, compared with 34% of the control group. After 21 years, runners had significantly lower disability levels than non-runners; their death rates from cardiovascular events, cancer and neurologic disorders were much lower than in non-runners — 65 of the runners had died of cardiovascular, neurologic and cancer events compared with 98 deaths in the control group.

“You’re 100 times better … as an athlete training in your 40s and 50s than a sedentary person in your 20s, any way you look at it,” Tarnopolsky says.