Weight fluctuations explained!

by Cynthia Sass, MPH, RD, PREVENTION I'll never forget the LONG debate I had with a friend of mine about why you CAN eat a pound of food without gaining a pound of weight. He disagreed, saying it was impossible, but I’m absolutely right. In fact, you can down several pounds of food without gaining an ounce, let alone a pound. Here’s why: in a nutshell, body weight is controlled by calories, and the weight of food has absolutely no relationship to its calorie level. The perfect example is water. A gallon weighs eight pounds, but water has no calories, so you can’t gain body fat by drinking it, even though it’s quite heavy. In order to gain one pound of fat, you need to eat an excess 3,500 calories (on top of the number you burn off). So if you typically burn 1,500 calories in a day, you’d need to eat at least 5,000 calories within 24 hours to gain an actual pound of body fat. And 3,500 calories worth of food can weigh a lot or a little. Each of the following contains about 3,500 calories, enough to create a one pound fat gain if not burned off: 1 pound of butter 5.5 pounds wild salmon 10.5 pounds of grapes 21 pounds of raw broccoli When you step on the scale, you're weighing everything that has weight, not just muscle, bone, and body fat, but also water, undigested food (even if it will all later be burned off), and waste your body hasn't eliminated yet. The latter three are why your weight on a scale can shift very quickly, from day to day or hour to hour--even if your muscle and body fat remain exactly the same. Sodium’s another factor. It’s attracted to water like a magnet, so if you eat something salty (say salted nuts), you’ll probably retain more water (temporarily) than if you ate unsalted nuts. And as I’ve shown above, certain foods weigh more, even when they don't provide more calories. So the next time you step on the scale, if it’s creeped up a bit, don’t panic. Ask yourself a few questions: Have I been eating “heavy” foods (even if they’re low cal)? Am I well hydrated (or could I have been dehydrated the last time I weighed)? Have I had anything especially salty? Am I constipated? Have I eaten enough excess calories to cause this much of a weigh gain (i.e. if your weight spiked by 2 pounds, have you really eaten 7,000 excess calories since your last weight in)? Fluctuations are normal. There are numerous factors that affect the number on the scale that have nothing to do with changes to your “fat mass.” So if you weigh yourself daily, look for a pattern over time instead of focusing on every spike and dip, and don’t forget to put those digits in perspective.