When you exercise, you burn carbohydrates, such as sugar. If you exercise long and hard enough, you burn fat too. Currently, the only way to know for sure when you're actually burning fat is to measure biomarkers in blood or urine, which is obviously problematic if, say, you're in the middle of a swim or long run.
Swiss researchers, however, have developed a small sensor that detects the presence of a particular biomarker that is expelled with breathing: acetone. (It leaks into the breath from the blood supply feeding pulmonary alveoli in the lungs.
The sensor is about the size of a quarter, and appears reasonably accurate in tests. Researchers are working to make it more efficient and smaller. They're also working on chips to detect airborne biomarkers that test for kidney function and lung cancer.
Iowa State scientists say adding a bit of soybean oil to your salad boosts the body's ability to absorb seven different nutrients in salad vegetables, such as vitamin E and K. That's good news for dieters worried about the added calories of salad dressing, though researchers still cautioned restraint. U.S. dietary guidelines recommend about two tablespoons of oil per day. Another reason not to go overboard: The study was small, just 12 participants.
Body of Knowledge
A knee jerk reflex takes about 30 milliseconds, or 30 one-thousandths of a second.
Get Me That, Stat!
The National Center for Family & Marriage says 13 percent of American adults lived alone in 2015, up 1 percent since 1990. The share of people under age 45 and over age 65 hasn't changed much, but the middle years -- 45 to 65 -- have a lot, which has some demographers worried since loneliness is linked to a host of physical, mental and social ills.