Despite a growing understanding of the benefits of resistance training and high intensity interval training, the nation's go-to fat loss tool still seems to be going out for a jog. Every January we hit the pavements (literally.... again and again and again) with the best intentions. Unfortunately, it turns out jogging is in fact a very flawed fat loss tool.
One reason for this is the idea that the best way to burn fat is to perform long bouts of slow, tedious aerobic exercise. This misconception actually stems from peer-reviewed sports science research. The research shows that we burn the highest proportion of fat for energy at submaximal intensities. What this ignores is the total amount of energy required by the exercise and the amount of energy we burn once the exercise has finished.
A smaller percentage of something big can be greater than a larger percentage of something small! Therefore generally speaking, the harder you train the more fat you will burn. If we also take into account the additional energy we burn after the exercise, referred to as EPOC (excess post-exercise oxygen consumption) in the scientific literature, we can see that we burn more energy after high intensity exercise as well as during it.
The biggest problem I have with jogging is the repetitive impact forces. Biomechanics research shows us that we are subjected to forces greater than double our bodyweight going through one leg with each stride while running. Combine this with the fact that many individuals jogging to lose body fat are both overweight and possess little muscular strength and you have a recipe for joint problems.
It is also extremely difficult to apply the principle of progressive overload to your jogging, which makes it difficult to make continual improvements and adaptations. It is easy to lift one extra kilogram, perform one extra rep or increase the duration of a sprint interval by five seconds. It is more difficult to run 10km 20 seconds faster every week or run an extra 50m with each training run.
Another major problem with long bouts of low intensity exercise is that over the long term it will lead to a loss of muscle mass. This will reduce resting metabolic rate and actually worsen many markers of good health. Resting metabolic rate is generally the greatest contributor to the total number of calories we burn each day, so this has obvious implications to fat loss goals.
Jogging for weight loss also encourages people to tackle weight loss from a calorie approach (count your caloric intake and attempt to burn off more than you consume). This method has many limitations. It does not take into account the macronutrient ratio of the diet and the influence of this on hormone levels and the thermic effect of feeding. A calorie deficit also leads to the loss of lean body mass as well as fat mass. The long term success rate of calorie counting diets is generally estimated to be around 5% in the general population! Combine this with the fact that it is not an enjoyable experience and we can start to see that this may not be the way to go.
All things considered, I believe there is a pretty strong case for us to reconsider jogging being the first point of call for overweight individuals. High intensity interval training and resistance training are more effective options. In cases where these options are not appropriate (due to a lack of facilities, knowledge or the presence of certain orthopaedic issues), I would favour lower impact modes of aerobic exercise like walking or swimming.