Your weight as a number is incredibly fickle. It can rise and fall from day to day, even hour to hour, and shifts in body fat are rarely the culprit. When you step on the scale you're not just measuring muscle and fat. That number also represents the weight of your bones, organs, bodily fluids, glycogen (the form of carbohydrate you stow away in your liver and muscles, which serves as a back-up fuel, like an energy piggy bank) and the waste inside your digestive tract that you haven’t yet eliminated. Given all of these variables here are three common reasons you may see a bump up on the scale, even while you're losing body fat:
You Ate a Little Too Much Sodium
Water is attracted to sodium like a magnet, so when you down a little more salt or sodium than usual, you may hang onto extra H20. Two cups of water (16 oz) weighs one pound, so a shift in fluid will have an immediate impact on your weight on the scale.
The Fix: Drink extra water — it may seem counterintuitive but it will help flush out the water you’re hanging onto. Potassium rich foods are also key, as they have a natural diuretic effect — great choices include a small banana, lima beans, cooked spinach, beats, nonfat yogurt, cantaloupe and honeydew melon.
Being “backed up” can cause you to weigh more until your body releases the waste it’s hanging onto. It’s not uncommon for women to experience constipation as part of PMS (lucky us!), but stress, too little sleep, and travel can also be triggers.
The Fix: Drink more water and eat foods rich in soluble fiber to get things moving, like oats, barley, figs, beans, chia and flax seeds and citrus fruits.
You’re Storing More Carbs
Your body has a huge capacity to store carbs — you can sock away at least 500 grams. To put that in perspective one slice of bread packs 15 grams of carbs. When you eat more carbohydrate than your body immediately needs, you'll store the leftovers in your liver and muscles, which will stay there until they're needed for fuel. And for every gram of glycogen you stockpile, you also put away about 3-4 grams of water, so essentially it's a double whammy when it comes to your weight.
The Fix: Cut back, but don’t cut out carbs, and focus on quality. Ditch refined, dense carbs like white breads, pasta and baked goods, and include a small amount of a whole grain at each meal, like steel cut oats, brown or wild rice or quinoa, and round out your meal with fresh veggies or fruit, lean protein, and a little plant-based fat. A great example: a small scoop of wild rice topped with a stir-fry made from a variety of veggies sautéed in sesame oil, along with shrimp or edamame.
Bottom line: it’s actually normal for your weight to ebb and flow, so if you see a slightly increase, don’t panic. To gain just one pound of actual body fat, you’d have to eat 3,500 more calories than you burn (think 500 excess calories every day for seven days straight — 500 is the amount in three handfuls of potato chips, or a slice of pecan pie, or one cup of premium ice cream). If your weight on the scale increases by one pound and you haven’t consumed an excess 3,500 calories, you haven’t actually gained a pound of body fat. So shift your focus away from the scale and toward how you look and feel. It’s very possible to see more muscle definition and even a reduction in inches when your weight in pounds hasn’t budged.
Cynthia Sass is a registered dietitian with master's degrees in both nutrition science and public health. Frequently seen on national TV she's a SHAPE contributing editor and nutrition consultant to the New York Rangers and Tampa Bay Rays. Her latest New York Times best seller is Cinch! Conquer Cravings, Drop Pounds and Lose Inches.