This is a question every fitness professional hear’s hundreds maybe thousands of times over the course of their careers and almost on a daily basis .
The simple (and complex) answer is that there is no “best way”. Each and every client will respond differently to a training program, however there are some principles fitness professionals can apply when designing their programs.
Activities which require many muscle groups and are weight bearing use more calories per minute and are therefore better suited for fat loss than non weight-bearing activities that do not use many muscles.
This is were the sports science comes in .
It is often assumed that low-intensity exercise is best for burning fat. During exercise at a very low intensity, fat does account for most of the energy expenditure, while at a moderate intensity, fat accounts for only about 50 percent of the energy used. However, since the number of calories used per minute is much greater at a moderate to high intensity than at a low intensity, the total number of calories expended during a moderate- to high-intensity workout is greater than it is during a low- intensity workout of the same duration; consequently, the total number of fat calories expended is also greater during the higher-intensity workout. The rate of energy expenditure, rather than simply the percentage of energy expenditure derived from fat, is important in determining the exercise intensity that will use the most fat. Furthermore, endurance-trained individuals rely less on carbohydrates and more on fat as a fuel source during submaximal exercise (Kiens 1997). Thus, the more aerobically trained your clients become, the more fat they will use during subsequent exercise sessions.
To decrease body fat percentage, your clients do not necessarily have to use fat during exercise. Much of the fat from adipose tissue (as opposed to intramuscular fat, which is primarily used during exercise) is lost in the hours following exercise. Moreover, the amount of fat lost after a workout depends, in part, on the exercise intensity during the workout. Following high-intensity exercise, the rate of fat oxidation is higher than it is following low-intensity exercise (Mulla et al. 2000; Phelain et al. 1997). Because clients can perform a greater intensity of work if the work is broken up with periods of rest, interval training is a great way to perform high-intensity work and help decrease body fat percentage.
Both strength training and endurance exercise have been shown to decrease body fat percentage. A combination of endurance and strength training results in more fat loss than either exercise regimen alone.