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Sat October 29, 2011
Eating Your Way To A Healthy Heart (If You're A Python)
It's a huckster's dream: "Try the new Burmese Python Diet. No calorie counting or special foods. Eat whatever comes along, up to a quarter of your body weight. Not only is it good for your waistline; it's good for your heart."
Trouble is, what works in pythons probably won't work for humans.
Pythons employ what scientists call a "sit and wait foraging tactic." In other words, they lie around in a Burmese jungle and wait for the food to come to them. And of course, this can mean months between meals.
Still, these infrequent but humongous meals are actually normal for the python. A python's heart gets far larger and stronger after it gorges, and scientists are trying to understand how that happens, and whether it can help humans with heart diseases.
Heart growth isn't always a healthy thing. A diseased heart can get larger as well. But like any other muscle, the heart will grow larger and stronger after it gets a prolonged workout.
"Lance Armstrong and Michael Phelps undoubtedly have huge hearts," says University of Colorado biologist Leslie Leinwand. But the growth a human heart is capable of is nothing compared with what a Burmese python can do after it eats a big meal.
"Within two to three days [the snake] can get anywhere between a 30 and 40 percent increase in the mass of the heart," says University of Alabama snake expert Stephen Secor. The growth comes following a meal, because the large meals pythons infrequently eat send their metabolism through the roof and put huge demands on their hearts.
Secor and Leinwand have a paper out in Science Saturday in which they show that it is the ratio of three fatty acids in the blood that prompts the heart growth in snakes. They found that the same ratio of fatty acids injected into a mouse will cause its heart to grow as well.
So why won't eating a large meal cause a human's heart to grow? Part of the answer is the scale of our meals relative to our size.
"Could you swallow a totally intact meal that weighs a quarter of your body mass?" asks Secor. In other words, could you eat a 30- or 40-pound pig in a single sitting? "If you could, I guarantee you your metabolic rate would go through the roof," says Secor.
Of course we're not designed for such meals. But even if we could consume a whole pig we'd have to digest bones, hair and all. And that could cause some major problems — most food we do eat undergoes some amount of processing that makes it possible to eat.
So even though we're all keen on stronger hearts, we'll probably have to leave the Burmese Python Diet to the Burmese python.