Lumen Review

In this Lumen review, Mike Harris assesses the metabolic analyser to see if it can help with weight loss and improved wellbeing

(Image credit: Lumen)
Golf Monthly Verdict

One of the biggest keys to losing weight lies in having a better understanding of your metabolism. If you’ve got the time to dedicate to Lumen, the level of personalised insight it provides is incredible and could help you to truly optimise the weight loss process.

Reasons to buy
  • +

    Ultimate personalised data and advice

  • +

    Easy to navigate app

  • +

    Useful tutorials and insight

  • +

    Premium materials and aesthetics

  • +

    30-day free trial

Reasons to avoid
  • -

    Onerous to input a the amount of information needed to get the optimum insight

  • -

    High initial device costs and a monthly subscription after a 30-day free trial

Why you can trust Golf Monthly Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you. Find out more about how we test.

Anyone who’s tried to lose weight will know it’s not an easy process. Two steps forward one (sometimes two) steps back. Everyone needs a bit of help with the process and finding the 'thing' that cracks the code for them. 

It’s different for different people but for me it was gaining a proper understanding of my metabolism and what foods to eat (and when) to keep my insulin levels from spiking, feeling full for longer, avoiding snacking to know that when I was exercising my body was burning the right fuel for performance and weight loss. In short it was to eat fewer carbohydrates (and when I did to eat slow release ones) and balancing the lean protein with good fats - essentially monitoring my macros. 

Gaining that understanding took me a long time, a lot of research (reading articles, books and watching YouTube videos) and a fair bit of trial and error. If Lumen had been around when I started my journey, it would have definitely fast tracked my progress!

Small Breathalyser, Big Insights 

Lumen, which looks a bit like an inhaler or vaping device, is a small breathalyser equipped with Bluetooth to sync with an app. To use it, you simply place your lips over the device, inhale, hold your breath for 10 seconds, exhale, and then await the results. In short, by monitoring the CO2 levels in your breath, it tells you what your body is currently burning for energy – carbohydrates or fat – so you can understand what’s happening with your metabolism. 

Unquestionably, one of its biggest benefits is that it’s so personalised. It measures your breath. In other words, it’s not giving generic advice and insight. Armed with this information, and with a super intuitive app, you get your own personalised nutrition plans for the day, one that can be adapted for your goals (be they weight loss or fitness focused) and your own eating habits. 


(Image credit: Lumen)

One of the most appealing aspects of Lumen, is that rather than sending you down a road where you’re restricting your calorie intake, this device helps you to focus on eating the right balance of carbohydrates, fats and protein. Advice is focused on not overeating carbohydrates but, as I’ve said from my personal experience, eating the right type of carbs at the right time was transformative for me.

To get the most use out of Lumen, you do need to assign a fair bit of time - and then stick with it. It takes two weeks to establish a solid baseline and you’re required to take readings multiple times a day: ideally when you get up in the morning before you’ve eaten, pre and post exercise, before and after consuming meals and pre bedtime, and while these don’t take long to do - around 2-3 minutes max from opening up the app, turning on the Lumen and measuring the breaths - when added together it is a not insignificant amount of time. 

If you use a wearable or use an app that requires input such as Whoop or My Fitness Pal, it can all start to feel quite onerous to measure and log variables. However, to get the most from Lumen you do need to be disciplined about using it. 

That said, the feedback that Lumen gives you is really interesting. What I would say is that if I’d had this product five years ago, when I first started my health and fitness journey, this would definitely have helped me accelerate my learning about how the body burns different fuels, and how to optimise weight loss.

Mike Harris
Content Director

Mike has been a journalist all his working life, starting out as a football writer with Goal magazine in the 1990s before moving into men’s and women’s lifestyle magazines including Men's Health, In 2003 he joined Golf Monthly and in 2006 he became only the eighth editor in Golf Monthly’s 100-plus year history overseeing the brand until July 2023. His two main passions in golf are courses, having played over 400 courses worldwide, and shoes; he owns over 40 pairs.

Mike’s handicap index hovers at around 10 and he is a member of four golf clubs: Hartley Wintney, Royal Liverpool, Royal North Devon and the Royal & Ancient Golf Club of St Andrews.