Frequently Asked Questions

The Science

  • Metabolism is the sum of all life-sustaining reactions in your body. Calorify measures the total energy required to keep your ~37 trillion cells working properly. Each cell is a little factory doing work to keep you alive: thinking, healing, digesting, playing, growing… you name it!

  • Doubly labeled water is pure water (100% H₂O). Each water molecule is fingerprinted (“doubly labeled”) with extra neutrons, which allow us to track the movement of water and energy through your body over the course of your test.

  • The Calorify test uses doubly labeled water to measure how much oxygen (O₂) you turn into carbon dioxide (CO₂). This process is called cellular respiration and occurs when your cells work (turn food into energy). Calorify measures how much work your cells perform over the course of the test. You can think of it as a sensor measuring the amount of exhaust coming out of a car to measure how much fuel it burns: Calorify accurately measures your gas mileage.

  • In short, no. The doubly labeled water method provides the only precise measure of metabolic rates in free-living individuals, allowing for the measurement of you performing your usual day-to-day routine (including exercise, diet, and sleep).

    The second best option would be getting measured in a clinical setting, which requires being invited to participate in research and isolating for days on end in an inpatient metabolic chamber. This option, while technically accurate, doesn’t provide you with the full picture of your metabolism, as you aren’t able to exercise, eat, or go throughout your life in a normal way. When compared side-by-side, whole-room calorimetry and the doubly labeled water method produced measurements of comparable accuracy and precision (Melanson et al. 2018).

    All other products that claim to measure metabolism are purely guessing. They estimate based on your age, weight, height, and sex. While this sounds good in theory, they can be off by thousands of calories. Why? Because your metabolism is uniquely you: based on your cells, your lifestyle, your diet, your exercise, your genetics… you get the picture. At Calorify, we empower you to stop guessing and start measuring.

    The doubly labeled water method has also been shown to provide body composition measurements of comparable accuracy and precision to DXA scans (Melanson et al. 2018).

  • Of course! We love getting into the nitty gritty details here at Calorify. For a deep dive into the science behind each metric, visit our PRO Results Guide page.

    Since the doubly labeled water method has been used in humans for over 40 years, there are hundreds of peer-reviewed studies. Here are some of our favorites:

    For some less technical reading, check out the these pieces written by our Scientific Advisor, Dr. Herman Pontzer. His work has been profiled on the cover of Science and Scientific American. His book, Burn, presents an outstanding overview of the cutting edge science of calories driven by the doubly labeled water method.

The Kit

  • Calorify PRO includes all the data contained in the standard results as well as additional metrics designed for athletes (complete energy budget, energy availability, training sustainability), a consultation with our team, and a custom plan to help you achieve your body composition goals. Here’s a sample report of the PRO results.

    We typically recommend Calorify PRO if you are:

    • an athlete;

    • looking to optimize your energy budget for performance;

    • struggling with training plateaus;

    • suffering from recurring injuries;

    • searching for a custom body composition plan; and/or

    • interested in reviewing your results with our team (and your coach, trainer, doctor, or nutritionist, if desired).

    Note that, in order to unlock all the exclusive metrics included in the PRO report, you will need to upload your macros and exercise data from the test period to our data portal after completing your test (see the instruction card in your kit for details).

  • Your Calorify kit includes a bottle with a sip of doubly labeled water, three sample collection cups, three transfer pipettes, three sample tubes, a sample card (to record your weights and the time of your samples), and prepaid return packaging to send your samples back to our lab.

    See our quick how-to video for an overview of the kit contents.

  • Each dose of doubly labeled water is personally tailored with the information provided in your intake form (completed during the check-out process). For this reason, you cannot give your kit with someone else and the information provided in the intake form must match the person who takes the test.

  • Nope! As long as your bottle of doubly labeled water remains unopened, your kit will remain safe and stable.

    One thing to note is that the prepaid shipping label on your return box will expire 3 months after purchase (our team will make sure to send you reminders if that cut-off gets close).

  • No worries, it happens to the best of us. See below for the files:

    Sample Card

    Instructions

The Testing Experience

  • The test takes one week to complete.

  • We promise it isn’t hard! Here’s a quick how-to video to walk you through the process.

    On day 1, you’ll collect your first urine sample and weigh yourself. Then, you’ll drink your sip of doubly labeled water. After 4-6 hours, you’ll collect your second urine sample. Seven days later, you’ll collect your final urine sample and weigh yourself again.

    You will also need to provide at least 3 additional weights during the course of your test (see the back of the sample card in your kit) if you would like calories eaten and resulting deficit/surplus data reported in your results.

    Detailed instructions can be found in your kit and are also available here: Instructions

    You also have the option to sign-up for guided test reminders to keep you on schedule. Text “GUIDE” to (669) 266-2876 and follow the instructions once your kit arrives.

    Looking for even more tips? Check out our blog post on getting the most out of your test.

  • Nope! Rest assured our lab has created a dose of doubly labeled water tailored just for you. The typical dose is about 1 fl. oz… basically just a sip.

    The reason for the small volume is that we leave a lot of room in the bottles for the big athletes we test (think pro sports players) who sometimes require a larger dose due to their strenuous training load.

  • In order to unlock all the exclusive metrics included in the PRO report, you will need to upload your macros and exercise data to our data portal after completing your test (see the instruction card in your kit for details).

  • We pack a lot of information into your results! The data we report back to you includes information about your:

    • Energy balance: calories burned, calories eaten and resulting deficit/surplus (if additional weigh-in data is provided)

    • Calorie intake by objective: maximum safe fat loss, burn fat while building muscle, maintenance, build muscle, gain weight

    • Energy budget: physical activity level, basal metabolic rate

    • Body composition: lean body mass, fat mass, body fat percentage

    • Hydration: water throughput, body water percentage

    If you’re interested, here is a sample report of the results. Once you receive your results, check out our results interpretation page to dig into each metric and review additional resources and content.

    In addition to the metrics included in the standard report, each Calorify PRO report includes the following exclusive training metrics:

    • Complete Energy Budget (with provided macros and exercise data)

    • Energy Availability (with provided exercise data)

    • Training Sustainability

    Here’s a sample report of the PRO results.

  • To accurately provide you with the full set of results, we require precise weights taken throughout the testing process. We recommend buying a scale, going to your gym, or borrowing one from a friend for the week if you need to.

  • In order to provide the most accurate results, we want to make sure your body is in its ‘usual’ or ‘normal’ state. This means that it’s probably best to wait starting the test until that bad hangover has subsided or you’ve recovered from your ultramarathon race. The ‘best practice’ of the Calorify method is to take your first and last samples on an empty stomach before eating breakfast.

  • Not at all! The only thing we measure is the water in your returned samples. However, if you are sick with vomiting or diarrhea, you may want to wait to start your test, as you’re likely under-hydrated (which can affect your results: see above).

    Additionally, you can have confidence that the menstrual cycle doesn’t impact the gold standard measurement of TDEE. But, the cycle could impact body composition and energy intake metrics if effects of fluid retention are particularly noticeable (aka bloating; see White et al. 2011 for more information on how fluid retention is related to the natural menstrual cycle).

  • The Calorify test precisely measures tiny amounts of fingerprinted water in your samples. At home, you’re likely drinking similar water each day, but when you travel, you may drink water that has a totally different ‘fingerprint’. This can affect your results by changing the ‘baseline’ signature of the water in your body.

  • Yes. Doubly labeled water has been used at elevations of up to 8,850 m and demonstrated to be accurate for both body composition and total energy expenditure.

    Effects of increasing altitude–including decreasing barometric pressure, absolute humidity, and temperature–on total energy expenditure are all measurable via DLW testing, including oxygen consumption economization, limited physical performance, environmental hypoxia, and effects on energy intake, water throughput, and intestinal absorption.

  • In order to provide the most accurate results, we want to make sure your body is in its ‘usual’ or ‘normal’ state. This means that it’s probably best to wait starting the test until that bad hangover has subsided or you’ve recovered from your ultramarathon race.

    That’s why the ‘best practice’ of the Calorify method is to take your first and last samples on an empty stomach before eating breakfast.

  • If you forget to take Sample B within 4-6 hours after Sample A, take it as soon as possible, but don’t worry too much. We’d rather have you be a little late than too early on this one. Please make sure to note the date & time on your sample card.

    If you forget to take Sample C one week after Sample A, take it as soon as possible, but (again) don’t worry too much. The test allows for a fairly flexible window that should capture your results accurately, even if you’re a day late - just remember to note the date & time on your sample card.

    Remember that you also have the option to sign-up for guided test reminders to keep you on schedule. Text “GUIDE” to (669) 266-2876 and follow the instructions once your kit arrives.

  • Good news: the Calorify test is safe for all! The method has been funded by the federal government for use in humans for over 40 years and has no known physiological effects or safety concerns.

    Doubly labeled water contains versions of water molecules that occur naturally in drinking water and are already inside our bodies at lower concentrations. The method has been used in hundreds of peer-reviewed scientific studies and is routinely used in vulnerable groups, including those who are pregnant or nursing, elderly, children, and infants – all with no reported adverse effect.

  • Doubly labeled water has been used in patients with renal failure, and demonstrated to be accurate for both body composition and total energy expenditure. All stages of renal failure have been tested and, in all cases, DLW was used as the gold standard for which to benchmark other methods or equations. Variance in energy expenditure seen across patients with renal failure can be attributed to age, body composition, and physical activity, rather than related to glomerular filtration rate.

    While reduced urine production (oliguria) or post-void urine retention in the bladder will increase the time to reach isotope equilibration into urine, testing is still possible with minor alterations to the standard two-point protocol. As the time for equilibria to occur between body water and the ingested isotope dose is lengthened, the investigator may choose to extend the schedule for the post-dose urine specimen up to 24 hours. Ongoing treatment with diuretics should have little to no effect on the DLW technique.

The Company

  • Calorify is the first lab to commercialize this precise method of measuring metabolic rates. While the science has been around for over 40 years, tests have been limited to those participating in academic research (less than 15,000 people). We’re excited to democratize what we believe is one of the most important data points about your body.

  • We’ll be honest: it’s hard work! Calorify runs the largest lab of its kind in the world, but it takes intimate knowledge of the science, technical processes, and business know-how to make it all work – and that’s why we’re so proud of our team!

  • At this time, the Calorify kit is not a "qualified medical expense" as defined by the IRS for HSA or FSA purposes, but we'll be sure to make an announcement if that changes.

Something still not clear? Have more questions?

Reach out to our support team at any time:

support@calorify.com | (669) 266-2876