by Andrea Hundley
How obtained: review sample from Lumen
RBR Sponsor: no
Have you ever wondered how to tell if your body is burning fat? There are many devices out there that will tell you if you are in ketosis, but they require you to use blood or pee on a strip of paper. Lumen is the first device that can answer this question just using your breath.
Ketosis is the state that your body enters when you’ve used up all the carbohydrates in your system and your body starts to use fat for fuel. Keto is a popular ultra low carb diet with a goal of keeping you in ketosis all or most of the time, but you don’t have to be on a keto diet for your body to burn fat instead of carbs.
Your body should have the metabolic flexibility to go back and forth between burning sugar and fat if you are healthy. One example of an inability to go back and forth is insulin resistance — a problem where your body is not able to respond well to insulin and unable to properly burn the glucose in your bloodstream, and can lead to more serious problems like Type 2 diabetes.
Using the Lumen can help you learn exactly which foods are increasing your blood sugar. This can help you plan your diet to avoid the foods that are causing the biggest problems for you or only eat them in moderation or when you plan to exercise. You can also use it to see which types of exercise, intensity levels and lengths of time can help you bring your blood sugar back down and keep it in a healthier range.
I was excited to learn about the Lumen because of these insights about how your metabolism works over time. It’s even portable so you can take it with you and use it throughout the day. I have been using the Lumen for several weeks now to try it out for myself and see how it works. Lumen provided the device to me at no cost so that I could review it.
How the Lumen Works
The Lumen uses your breath, sometimes one breath and sometimes two, to analyze the CO2 you are putting out. This allows the device to determine if your metabolism is burning fat, carbohydrates or a mix of the two. When your CO2 is high, that signals that you are using more carbohydrates. When your CO2 is low, it means you are burning more fat.
The device gives you a score ranging from one to five after each test. If your goal is to burn fat, the ideal reading is a one or a two in the morning when you wake up. This means that during the night your body used all of the carbohydrates that you ate the night before. Carbohydrates are the easiest fuel for your body to burn and your body uses them first.
I had an onboarding call with a representative from Lumen and it was really informative. She explained to me that I could learn more if I measure my breath throughout the day like this:
- Measure 20 minutes after waking but before eating or drinking anything
- Measure before eating
- Measure 30 minutes before exercise
- Measure 30 minutes after exercise
- Measure after eating
- Measure before sleeping
- Custom check in – if you want to see how your body is reacting to a specific event
You don’t HAVE to measure your breath this many times, but if you do you can see how the foods you are eating affect what fuel the body uses. If you practice intermittent fasting you can also see how it’s working.
The lumen is designed to gather information about your individual metabolism for the first two weeks of use until it gives you a metabolism flexibility score.
Metabolic flexibility matters more as you age because many of the lifestyle related health problems we develop are tied to insulin resistance. You can read about the many health problems that are linked to insulin resistance here such as hypertension, type 2 diabetes and atherosclerosis. https://www.aafp.org/afp/2001/0315/p1159.html
You are considered to have more flexibility if you can quickly move from burning carbohydrates after a meal to burning fat. The longer it takes you to move into a “fat burning” state, the less metabolically flexible you are.
What Is the Science Behind Lumen?
If you want to learn more about the research behind the lumen read this article. The lumen was tested for accuracy against a blood test and the gold standard metabolic cart RER.
If you are asking yourself, as I did, what the heck is a “metabolic cart RER?” RER stands for respiratory exchange ratio. It is a measure of your CO2 output using a device that goes over your entire face. This device captures data from your breath and sends it to a computer that you are tethered to. It is not something that can be easily done at home, it is typically used in a doctor’s office.
The Lumens can give you the same information at home that you could previously only get in a doctor’s office with amazing accuracy.
What Good Does Knowing This Information Do?
First, the Lumen can tell you if your cycling is moving you into a fat burning state. When I first started using the Lumen I noticed that my waking number was three or four. I exercise in the morning before I eat anything. When I measured after a workout I was able to bring the number down, sometimes even to a one.
What this tells me is that my workouts, which are typically short and intense, are helping me to make my metabolism more flexible even if I eat lots of carbohydrates for dinner.
Second, the Lumen can help you to learn how many carbohydrates to eat. After your morning breath, you get nutritional goals, not in calories but in macros protein, fat and carbohydrates. These goals vary based on your reading in the morning AND the goals you establish when you set up the device.
The setup process asks you to choose between three goals: healthy weight loss, metabolic health and fitness performance. If your goal is to improve fitness there is even more fine tuning. You choose between increasing endurance, increasing muscle and improving body composition.
Based on your readings each day and your goals the Lumen suggests nutrition macros that differ each day. The program also adjusts these macros as your rating changes throughout the day.
Do I Have To Track Everything I Eat to Use the Lumen?
The Lumen makes daily macro suggestions for protein, fat and carbohydrates. BUT you don’t have to use a tracker at all. You can use the Lumen and adjust your eating on more of a trial and error basis. For example, you might eat a bowl of spaghetti and the next day you wake up and your breath measures a 5. You measure your breath throughout the day to see how quickly your body uses up that high carb meal.
You can begin to see how the carbohydrates you eat are being processed and how quickly. Even if you don’t track them exactly, you can see patterns that help you to make food choices each day.
If you practice intermittent fasting you can use the Lumen during the day to tell when you have switched over to fat burning. You can set up “custom” measurement periods that match your fasting goals. If you want to fast 12 hours, you can register a breath right before you are ready to eat and see if you’ve reached a fat burning state. If not, you can try extending your fast.
Training Provided by Lumen
When you receive your Lumen and load the app on your phone you will get four emails that will help you learn how to get the most out of the device. You also get the opportunity to schedule a one-on-one zoom call with a representative from Lumen who can answer any questions.
The first email explains exactly how to use the device. The nuts and bolts of how to measure your breath. You have to breathe in for a count of 10, hold your breath for another count of 10 and exhale for 10.
The second email explains the nutrition advice the device gives you each day. It explains how you CAN use the app with a nutrition tracker like My Fitness Pal or how you can estimate your macros if that sounds like too much work.
The third email explains metabolic flexibility. You get a flexibility score after using the Lumen for two weeks. This score is updated every week so you can see if you are moving in the right direction. The scientists behind the Lumen don’t believe that you should always be in a fat burning mode, they suggest higher carbs on some days because it can make you more metabolically flexible.
The fourth email explains what all of the different measurements mean and how you can use them to make decisions. What I found interesting about this is that you can actually go into a carb burning mode when you extend your fast too long.
Would I Recommend This Product?
I’ve used the Lumen for two weeks and I really find the information it gives me useful. It’s a great tool if you practice intermittent fasting. It’s also a great tool to measure whether your workouts are achieving your goals. I think it’s a far more enticing tool than using a ketone/glucose monitor which requires a lot of finger pricking.
The website has lots of resources if you want to dig deeper on how to use it, but I will definitely keep it up and see how I need to tweak my diet to meet my metabolic goals.
During this training I learned your breath signature is individual to you. It is based on two weeks of data and your age and sex. I highly recommend the Lumen if you’re at a point where you’re noticing belly fat or a few extra pounds that weren’t a problem in your 20s, 30s and 40s. It’s a great tool for hacking your body’s ability to burn fat.
Martin Sigrist says
Thanks, didn’t know this existed,
The most time intensive workouts that we do as cyclists are aimed at burning more fat but there is no way of knowing they are working without going to a lab.
There is bound to be some individual variation and if this helps me find out what works best for me it will be a great tool.
Soham Jethara says
Whats the advantage on the monthly subscription with the tracker (3 Months , 6 months 12 months). What features do you not have when your subscription expires?