User Guide

Table of Contents

  1. Introduction
  2. Diary
  3. Trends
  4. Foods and Recipes
  5. Profile
  6. Miscellaneous

How to Record Your Body Fat Percentage

In your diary, click the Add Biometric button Select Body Fat from the metric choices Record the value.

How to Calculate Your Body Fat Percentage

Knowing your body fat percentage will help us to provide you with a more accurate recommendation for your daily protein requirements. It is strongly recommended that you use the most accurate method described below that is available to you.

There are several ways to determine how much body fat you are carrying. Each has its pros and cons. I've listed them below in order of cost, complexity and accuracy, from lowest to highest:

Photo approximation

The easiest and least expensive way to gauge your body fat percentage is to take a photo of yourself in your underwear (the most painful part) and then compare it to photos of people at different body fat percentages. You can use the photos below or do an Internet search for "body fat percentage" and selecting the Images tab on the results page. This of course isn't the most accurate method, as it requires you to be objective about your appearance, but it can give you a very good idea of where you are and what the next stage in personal health actually looks like.

It is my hope that those of you who submit pictures like those below, along with an accurate body fat assessment, it will help us create an even wider range of real world photos that will help you more accurately estimate your body fat percentage.
Visual guide for Body Fat in Men
Visual guide for Body Fat in Men

Skin calipers

This low-tech method involves using an inexpensive, lightweight and hand-held device known as a skin caliper to measure the thickness of a fold of your skin and the fat that lies beneath it. Calipers cost anywhere between a couple dollars and a couple hundred dollars and resemble a small pair of tongs. They can measure distance down to a millimeter. They can easily be purchased on Amazon and come with comprehensive instructions and formulas that will calculate your body fat percentage.

Taken at specific locations on your body, caliper readings can help you determine the total percent of body fat. Although there is always the possibility of error, body fat calipers are one of the most time-tested and accurate ways to measure body fat. For results to be truly helpful, it's best to engage the help of another person — particularly for women, who need to measure the skinfold on the back of the upper arm, a difficult-to-reach area — and to use that same person to take your measurements each time. You'll also need to either perform some simple calculations on your own, or use an online calculator developed for just this purpose to translate those measurements into your body fat percentage.

Bioelectrical impedance analysis (BIA)

This approach can be as simple as stepping on a specific type of scale that measures body fat, readily available online for about $50. BIA sends an electrical signal through your body, where it will pass easily through lean body mass — which is up to 75% water, a good conductor of electricity — but be impeded by your fat tissue — which contains low amounts of water.

This measurement, along with other factors — such as your height, weight, age and sex that you enter into the device — is then used to calculate your percentage of body fat, lean body mass and other body composition measurements. Although the absolute value may be off a bit, a BIA scale is very accurate and typically very consistent. Even though the number might not be accurate it will accurately measure your body fat day-to-day variability, which is a far more reliable monitor than your body weight.

More Advanced Tools

Skulpt (Electrical Impedance Myography)

EIM, which was developed by a professor of neurology at Harvard Medical School, is a relatively new technology. Devices using this technology only recently came to market although they have been tested in hospitals for over a decade. This method is similar to BIA in that it uses electricity to determine certain qualities of your body tissue.

But an EIM device, such as the Skulpt Aim — a hand-held gadget about the size of a pack of cigarettes that you hold on a few different sites on your body. It uses a different current that is optimized to flow through fat as well as provide feedback about the quality of your muscles. It is also designed to be placed on specific muscles throughout the body, giving a detailed picture of how each strong each muscle group is and gathering specific fat readings from multiple parts of your body.

The Skulpt Aim claims to be three times more accurate than skinfold calipers and five times more accurate than bioimpedance. It is relatively expensive though — the device costs $149 — although it can be shared with family members, friends or clients. Skulpt is also coming out with a more-stripped down device, the Chisel, that also reads body fat percentage and muscle quality and that at the time of this writing is retailing for $99.

Bod Pod (Air Displacement Plethysmography)

This option involves sitting inside an egg-shaped compartment for five minutes or less as instruments measure how much air your body displaces. There's no discomfort associated with the test — some people report it feeling like being in an elevator or a plane that has just taken off — although you will need to sit still. The Bod Pod is one of the most accurate body composition tests available today. The only issue is that you will need to find a Bod Pod near you (visit to search for locations), and a single visit generally costs around $50. Also, you will need follow-up visits to determine if there have been changes in your body composition since your initial reading.