You are unhappy. It makes sense. You have been forking out for a monthly gym membership and putting in hour after hour of sweat inducing exercise, but weight is just not shifting. Worse than that, you have actually gained weight. Take some solace in the fact that you are not the only one. Reducing body fat in response to working out is hugely variable between individuals. There is no unique explanation why this is the case, and it may reflect a number of factors.  It differs between people.

The majority of individuals believe that the reason that they are not reducing their body fat levels is because they are not active enough or their exercise levels, intensity or type is incorrect or insufficient. However even when an exercise program is a applied synonymously, there are huge individual differences in weight and fat loss. So what are the moderating variables in determining the fat loss response to a workout program? The reasons may surprise you and may challenge conventional commonly held beliefs regarding exercise and fat reduction.

The Metabolism and Exercise

One of the most commonly held views regarding exercise and reducing body fat is that exercise increases metabolism, and subsequently the amount of fat being burned. Whilst this view is true of some individuals, for most individuals, there is little change in energy expenditure following exercise, and for some individuals the metabolism even decreases. Therefore the assumption that working out will increase metabolism and support fat burning, should not be taken for granted.

Exercise Methodology on Fat Reduction

The general consensus of opinion is that the best method of exercise to induce fat loss is cardiovascular exercise because it is performed at a lower intensity to resistance exercise and is associated with higher use of fats for energy..

Just as important as the proportions of carbohydrates and fats which are oxidised during exercise, is the oxidation of these substrates following exercise. Research suggests that the combination of cardiovascular training with resistance training is most effective in the oxidation of fats during and following exercise, compared to cardiovascular training alone (when performed for the same duration of time), indicating that exercise type and not volume is the greater predictor in fat reduction.

Genetics and Fat Loss

Genetics are a major factor in an individual’s capacity to reduce fat through exercise. There is nothing that you to change your genes. However it is important to recognise the important role that genes play. There are a diverse range of gene variations which influence an individual’s response to fat loss, such as appetite and insulin resistance.

Desire for Foods and Exercise

A factor which is rarely considered in consideration of fat loss in response to exercise is exercise induced desire for food types. There is a theory that only individuals who respond well to exercise do not experience changes in their preference for foods after exercise. Conversely, individuals who do not respond well to exercise express increased preference for all food types following exercise, in particular high fat sugary foods. A low carbohydrate and high fat diet is suggested for exercise non-responders as a method of reducing cravings for high fat sugary foods.

Fat Oxidation and Exercise

One of the measures used to determine the metabolism is individual’s respiratory exchange ratio, which is used to calculate the proportion of fats and carbohydrates utilised by the body for energy. Both fasting and postprandial (up to two hours following the consumption of food) respiratory exchange ratio has been shown to be elevated for 24 hours after exercise, but the response varies between individuals. Even at rest some individuals use carbohydrate as their main fuel source indicating that little fat is used for energy. Typically individuals who frequently carry out endurance activities oxidise most fats but even those individuals there is a large variance in respiratory exchange ratio.

The Respiratory Exchange Ratio and the Diet

One of the strongest variables which affects repiratory exchange ratio is dietary fat consumption. The body is capable of adjusting the source of fuel it uses for energy on the basis of the composition of the diet. Diets which have a high fat content often correlate with high fat oxidation and high carbohydrate diets correlate with high carbohydrate oxidation. High fat and low carbohydrate diets have been associated with fat loss and blood glucose control in obese individuals and those with insulin resistance. They have also been linked to lower repiratory exchange ratios during workouts, which suggests greater fat oxidation. Therefore if weight loss is not achieved from following a high carbohydrate and low fat intake, switching to a high fat and low carbohydrate diet may help.

Summary

It is apparent that there are numerous factors to take into consideration when determining the amount of fat that would be expected for a unique individual to lose in response to a specific exercise plan. It is important to recognise that there is an individual response to fat loss from exercise. It is important to not make comparisons with other individuals but to identify and focus on the variables which are in your control and to apply your knowledge to the way that you diet and exercise.