Like many other types of aerobic exercise, cycling is an effective way to lose excess fat. Whether you're biking on the road or using an indoor exercise bike, cycling for fat loss can boost your metabolism to help shed extra pounds.
However, the way you structure your cycling workouts can significantly impact your results when cycling to burn fat. Exercise intensity and duration plays a big role in determining the source of energy used by your working muscles.
Cycling to Burn Fat
During exercise such as cycling, your leg muscles have an increased demand for energy. In order to produce this energy, the body breaks down both carbohydrates and fats.
As explained in a January 2016 article published by Progress in Molecular Biology and Translational Science, the body primarily uses carbohydrates as fuel during high-intensity exercise — energy production from this source is two times higher than energy production from fats.
According to an article published in January 2018 by Journal of the International Society of Sports Nutrition, breakdown of fats for energy, or maximal fat oxidation, occurs when exercising at intensities between 45 to 65 percent of your VO2max — the maximum amount of oxygen your body can use during exercise.
Once you exceed these intensities, your body shifts toward burning more carbohydrates.
Determining Your Intensity Level
VO2max is typically determined while exercising in a lab and wearing a mask to measure the amount of oxygen used during activity. This testing is not accessible to most people.
However, you can still estimate your exercise intensity using the Borg Scale — a self-reported measurement of your rating of perceived exertion, or RPE. An article published in June 2014 by the Journal of Education and Health Promotion found a strong correlation between RPE and VO2max.
The Borg Scale ranges from a score of six up to 20, as explained by Harvard T.H. Chan School of Public Health. Level six activity — reading a book or watching television —requires no exertion. Level 20 activity is performed at maximum effort, such as sprinting the last part of a race.
Cycling in the recommended "fat burning zone" of 45 to 65 percent of your VO2max could correlate to a Borg Rating Scale of 13 to 14. This level of activity requires moderate effort and increases your heart rate and breathing, but you can still carry on a conversation without becoming short of breath.
Activities performed at a moderate level of intensity can also be maintained for longer periods of time. If your goal is cycling for fat loss, consider exercising for longer periods of time.
The 2018 Journal of the International Society of Sports Nutrition article also examined the effects of exercise duration on fat oxidation. Fat burn was most optimal after 90 minutes of sustained submaximal exercise.
Hit the Road Early
If you're a morning person, consider cycling before breakfast. Some research has shown that exercising in a fasted state can shift energy production away from carbs and toward fat stores. However, the intensity of your workout still matters.
A study published in 2015 by Nutrición Hospitalaria examined the effects of performing low-intensity aerobic exercise using a treadmill at 25 to 44 percent of VO2max in a fasted state. Results indicated a shift toward fat oxidation for energy when exercising on an empty stomach.
The article also points out that consuming a carbohydrate-rich snack during your workout — which is common during endurance training — will cause your body to shift back to burning carbohydrates for energy.
Not all research agrees with these findings. A small study published in November 2014 by the Journal of the International Society of Sports Nutrition also tested the effects of fasted-state exercise versus eating prior to exercise on overall fat loss.
Participants in the study followed a hypocaloric diet and performed one hour of steady-state aerobic exercise using a treadmill, three times per week.
All participants experienced a decrease in fat mass, waist circumference and body weight despite different training protocols. There were no significant differences between the groups.
The authors also point out that while fat burning might increase during fasted exercise, there is some evidence that the body compensates by burning more carbs later in the day.
The Bottom Line
If you aren't able to spend 90 minutes cycling for fat loss, all is not lost. Any type of cycling that contributes to a caloric deficit — burning more calories than you take in — will contribute to fat loss.
A study published in April 2018 by the Journal of Education and Training Studies examined the effects of spinning cycling training on body composition in a group of 12 sedentary women.
These individuals participated in a six-week program of spinning cycling sessions, three times per week for 30 to 60 minutes each time. Exercise intensity was initially low, but gradually increased as the participants' fitness levels improved. Results of the study revealed decreased body fat and increased lean body mass.
The authors of this article also pointed out that exercise is only a small part of the fat-loss equation. Diet has a big impact on your ability to lose body fat — even if you're consistently cycling.
Read more: Is an Exercise Bike Good for Cardio?
Follow Exercise Recommendations
According to the Department of Health and Human Services, healthy adults need at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic exercise per week to maintain a healthy weight. You'll likely need to exceed these numbers to lose excess fat.
As stated by the Mayo Clinic, you must burn about 3,500 calories to lose one pound of fat. Reducing your caloric intake by 500 calories per day can lead to weight loss of about one pound per week — a healthy weight-loss pace.
Add in some cycling to speed up your weight-loss efforts. According to Harvard Health Publishing, a person weighing 155 pounds can burn about 298 calories while cycling at a 12 mph pace for 30 minutes. However, the same activity will burn 355 calories for a person weighing 185 pounds — people who weigh more will burn more calories during exercise.
- Progress in Molecular Biology and Translational Science: "Exercise and Regulation of Carbohydrate Metabolism"
- Journal of the International Society of Sports Nutrition: "Understanding the Factors that Effect Maximal Fat Oxidation"
- Journal of Education and Training Studies: "Effect of Spinning Cycling Training on Body Composition in Women"
- Nutrición Hospitalaria: "Endurance Training in Fasting Conditions: Biological Adaptations and Body Weight Management"
- Journal of the International Society of Sports Nutrition: "Body Composition Changes Associated with Fasted Versus Non-Fasted Aerobic Exercise"
- Journal of Education and Health Promotion: "Study of the Relationship Between the Aerobic Capacity (VO2max) and the Rating of Perceived Exertion Based on the Measurement of Heart Beat in the Metal Industries Esfahan"
- Harvard T.H. Chan School of Public Health: "The Borg Scale of Perceived Exertion"
- The Mayo Clinic: "Counting Calories: Get Back to Weight Loss Basics"
- Harvard Health Publishing: "Calories Burned in 30 Minutes for People of Three Different Weights"
- Department of Health and Human Services: "Physical Activity Guidelines for Americans, 2nd Edition"