By: Jodie Shield, RD
Many of you have asked me what I think about body fat scales – are they accurate? What’s the best one to buy? Do they really measure body fat? Well I confess: my favorite scale – if there is such a thing- is the doctor’s office upright scale. You simply step on, slide the markers until they balance, then read your weight. However, I realize this type of scale doesn’t tell you your body fat, BMI or any of the other handy measurements many of us want to know so we can analyze our weight and health. So I went undercover to my local Bed, Bath and Beyond store and bought a body fat scale. Here’s what I discovered . . .
My first dilemma: so many scales to choose from! Since I use to write for Weight Watchers and love their updated eating plan, I bought one of their body fat scales and decided to give it a try. This particular scale provided five key measurements: weight (in pounds), body fat weight, body fat percentage, body water, and bone mass. In addition, it contained enough memory to allow me to program the scale for up to four users. Check out my review of the Weight Watcher scale at the bottom of this article.
How do body fat scales Work? Most of these types of scales use bioelectrical impedance. That is to say, they send a safe and very low electrical current through the lower half of the body. Since the electrical current flows more quickly through water and muscle than bone or fat, the scale measures the speed of the current. Then based on that number, the scale estimates body fat using a multi-step, mathematical formula. One thing you will want to be aware of which was new to me: if you are pregnant or have an electrical implant such as a heart pacemaker or defibrillator these scales are not recommended.
Are body fat scales Accurate? Good question but the answer depends on several things. Body fat scale readings can be thrown off by the following factors. In addition,the results may not be accurate for kids under the age of 16, or people with an elevated body temperature, diabetes or other health condition.
- Hydration. If you’re dehydrated or sweat a lot from exercise or your climate, you will have less body water for the electric current to flow through. The result: your body fat reading may be higher than it really is. And the opposite is also true. If you drink too much fluid, have a full bladder, or if you are a women experiencing water retention from your menstrual cycle, your body fat reading may be lower than it really is. For best results: be aware of what affects your fluid retention; weigh yourself once a week, on the same day and at the same time of day; wear the same clothes or none at all.
- Movement. The electric sensors in these scales are sensitive and work best when weighing stationary objects. Wiggling around or quickly hoping on the scale can interfere with your reading. For best results: always stand on the same area of the scale platform and stand still.
- Foot calluses. Some studies have found that having thick calluses on your feet may prevent the electric current from flowing accurately. For best results: shave those calluses. (Did anyone say pedicure?)
- Muscle. Heavy-duty weight training builds muscle which weighs more then fat. This can result in a higher body weight measurement which can throw off the arithmetic in the body fat and BMI formulas (To calculate BMI, visit my home page.) For best results: if you do a lot of resistance weight training, these scales may not be your best option.
Great Gadget Review for:
Weight Watchers Conair Body Fat Scale (model #WW78)
Pros: I was pleasantly surprised how accurate the Weight Watchers body fat scale was for me. My weight was spot on, BMI correct, and my body fat percentage matched the reading I had confirmed by a personal trainer at my local health club. The initial set up took awhile, but after that using the scale was quick and easy. And it was fairly inexpensive $29.99. (The majority of body fat scales ranged between $30-$50 dollars.)
Cons: The five different readings flashed by way too quickly. And I had no clue what they meant. The owner’s manual came with some excellent charts which I would recommend you hang nearby or keep handy.
Healthy Eating For Families Recommendation: 4 out of 5 stars