Hi Monique,
In your column about weight loss and body composition monitoring, you mentioned that scales that compute body fat should use a formula appropriate to athletes. Can you comment further about that means? What errors can be induced? I have an electronic scale that I know shows variability with hydration levels,but I was wondering what other errors could be involved.
Thanks,
DHDear DH,
Many cyclists now have a home monitoring scale that uses the principle of bioelectrical impedance (BIA) for body fat analysis, and have purchased a model designed for athletes. Since water is a good conductor of electricity and much of our body water is in lean mass, and since fat isa poor conductor of electricity, these principles have been applied to measuring body composition.BIA equipment comes in two forms. One form has an individual lie on their back and electrodes are attached to their right wrist and right ankle.The electrical current runs from the wrist to the ankle. In the home use form, you stand on your scale and in your bare feet and the electrical current runs from the right foot, up the right leg, down the left leg,and out the left foot. Both techniques measure the level of electricity that enters the system and then leaves the system, and then you know how much energy is “impeded” in the system. The greater the difference between the amount entering and exiting the system (less comes out than went in),the less muscle mass and body water, or more body fat you have. Because of its relationship to body fluid, as you are aware your hydration status can greatly affect this body fat analysis. In fact checking your body fat daily is just as inconclusive and overused as stepping on a regular scale daily. The reading simply provides feedback on body fluid and hydration levels, and the results are easily swayed by fluid shifts related to a number of factors including not properly rehydrating after training, checking body early in the morning before hydrating, or after a dehydrating experience such as a sauna. If you are not well hydrated for the reading, the electrical current will not be conducted as well through your lean mass, and the bodyfat level reading will be falsely higher.Other factors that affect how electricity is conducted through the body include the height of the athlete (the electrical current would run longer in a taller person), and the ratio of weight to height (this predicts the distance of the current and the composition of the tissues the current is running through). Age and gender are also factors in body composition prediction. That’s why you set these variables on your own machine and store these variables for each individual before testing. After setting your machine properly, the most important variable is to complete the test in a well-hydrated state and to be consistent in when you check your body fat. All body fat measurements (underwater weighing,calipers) measure body fat indirectly and have some degree of error in measurement. When you check your body fat levels, make sure that you are well hydrated and have an empty bladder. If your urine is pale in color you are likely well hydrated. It is also important that you have not exercised for at least 4 hours, but 12 hours may be even better. Tryto check body fat levels after a training rest day if possible. Being consistent with the time of day, as this allows you to have a good sense of changesin body levels over time and as the racing season progresses.
Monique
Instant gratification?
Ms. Ryan:
Thanks for your nutritional columns throughout the year.Your recent column mentioned in passing that good choices for whole grains include oatmeal, but not instant. The distinction interests me. I love oatmeal and prefer slow-cooked oatmeal. But as one of my weight-control strategies,I eat breakfast after I bike-commute to work. At work, I can make instant oatmeal in the microwave, but not slow cooked. What’s wrong with instant oatmeal?
Thank you,
ECDear EC,
Eating any oatmeal is good for your health, as long as you consume the right type. Currently the USDA recommends that adults should consume6 to 8 ounces of grains daily. While these recommend portions are easily achieved by cyclists, even those wanting to lose weight, it is recommended that at least half of these servings be from whole grains. Grains such as oats provide B vitamins, minerals, and dietary fiber. One of the most important benefits to eating oats is the water-soluble fiber that it contains as this type of fiber can help lower blood cholesterol levels. In 1997 the FDA allowed foods high in oat bran or rolled oats to carry a claim that these foods can lower risk of heart disease when part of a low-fat diet. Soluble fiber also extends the time it takes the carbohydrate ina food to reach your bloodstream, referred to as the glycemic index of the food. Oats come in many different forms. Steel cut oats are oat groats (wholegrain of the oat with only the outer hard husk removed) that have been cut into two to three pieces. Cooking time is longer for this type of oat. Next comes, old-fashioned rolled oats, which are made by steaming the oats and flattening them with a roller. You can also purchase quick cooking rolled oats that cook in about 5 minutes, and of course instant oats which are simply rolled oats that are cut finer to cook faster. Steel cut and old fashioned oats have 4 grams of fiber per serving, 2 of which are water-soluble. Instant oatmeal has 3 grams of fiber per serving, with 1 gram water-soluble.Of course depending on the brand and type of oats you may find some slight differences in these amounts. When choosing instant oatmeal, it is important to choose the right type. Instant oatmeal is often processed with salt, sugar, flavorings, and colorings. Check the ingredient list and Nutrition Facts label. Choose an instant oatmeal with at least 3 grams of fiber. Fiber helps you stay full longer,which can help with your weight control efforts, and also keep your stomach satisfied until lunchtime. Oats naturally have about 3 grams of fat per serving, so any more than that is added fat. Make sure there is no transfat or hydrogenated oil in the instant oatmeal. Instant oatmeal can also be highly sweetened, so look for those with little or no added sugar as this adds some empty calories to your diet.You can actually microwave old fashioned oats at work for a minute or two depending on the texture you want and may find this option more filling.If you want additional calories, add nutritious choices such as raisins,or other dried fruit, or healthy sources of fat such as almonds and walnuts.Adding dairy milk or soy milk to your oatmeal adds protein as well.
Monique