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ARU and Lumen Reveals the Impact of Low and High Carb Diets on Metabolic Response

by Lumen Editorial Desk · March 15, 2023 · 3 minute read
high carb and low carb diet

The peer-reviewed study utilized the handheld Lumen device to accurately measure the impact of nutritional lifestyle on metabolic state

What are the effects of carbs in a diet and on your metabolic state? We have some answers!

New research has emerged from a peer-reviewed study conducted together with ARU Cambridge Center for Sport and Exercise Science to assess the impact of low and high-carb diets on metabolic response using Lumen’s handheld device, as well as provided insights into the effectiveness of the device in measuring metabolic health using CO2 levels through breath - in a manner similar to the Douglas bag method, a gold standard method used to assess metabolic state.

Dr. Merav Mor, Co-founder, and Chief Scientist at Lumen, stated that "Prior to Lumen, the only way to measure your metabolic health was in a lab. This study reveals how Lumen can be used to measure the direct impact of your lifestyle on your body in real-time." Dr Mor added, “We discovered that when following a high-carb diet, participants' metabolic state shifted to using carbs for energy, while when following low-carb diet, their metabolism switched to using fats as fuel”.

Research on CO2 levels after carb meals

The study, published in the Journal of the International Society of Sports Nutrition, revealed how the Lumen device detected significantly higher CO2 readings after a high-carb meal, in a manner similar to the Douglas bag method, which is the gold-standard method to assess metabolic status. Elevated CO2 levels in the breath signal a carb-burning state, while lower levels indicate the body uses mostly fat as an energy source.

Researchers also found that acute carbohydrate intake affects the metabolic readings (Lumen levels) across all measurements during the day, highlighting a significant difference between metabolic conditions for low-carb and high-carb diets.

The participant methodology involved twenty-seven recreationally active adults who followed a high-carb or low-carb diet for a week, then switched to a low-carb or high-carb diet after a wash-out period. Throughout this period, the participants took end-of-day, morning, and after-meal measurements. This provided the researchers with the ability to cover the participants' metabolic state over their entire daily cycle under regular conditions.

The most effective approach, according to researchers, for measuring metabolic response through the Lumen device following a high-carbohydrate diet may be better assessed under fasting conditions, while measurements after breakfast may be better suited for monitoring low-carbohydrate diets.

The study found that a high-carb diet resulted in significantly higher CO2 readings, indicating that the participants' metabolic state had shifted to using carbs for energy.

“In this study, Lumen was further validated as an effective at-home metabolic tracking tool which is part of our journey to making metabolic testing accessible to the academic and scientific community. We’re proud to work with ARU Cambridge Center for Sport and Exercise Science to further metabolic health research,” added Dr. Shlomo Yeshurun, Head of Research at Lumen.

The takeaway

This study provided valuable insights into the impact of low and high-carb diets on metabolic response and the effectiveness of the Lumen device in measuring metabolic state. The findings from the Lumen and ARU Cambridge Center for Sport and Exercise Science study act as a baseline for future studies analyzing the impact of exercise and lifestyle on metabolic response.


Lumen is a metabolism tracker that can provide numerous insights about the metabolic state of an individual, as well as valuable data to increase knowledge of metabolic flexibility and nutrition.

In a study conducted by San Francisco State University, Lumen has been peer-reviewed to meet the gold standard for metabolic measurement.

Our contributing team of in-house registered and certified nutritionists, dietitians, scientists, and researchers helping people become metabolically healthier

Lumen Editorial Desk

Our Lumen editorial desk includes an in-house team of certified and registered nutritionists and dietitians, scientists, researchers, and writers.