Fat loss

The most often mentioned training goal

There is no other training goal that is mentioned more often than losing body fat. Unfortunately only a minority of people is reaching that goal. Too often, required readiness and energy for changing live style in activity and nutrition are lacking. Combined with ignorance of metabolism, weight loss is often doomed to failure in advance.

Even though the “energy-balance” is easy to understand, its practical implementation is anything but easy. In most cases, eating habits and chronic lack of exercise are too deep-rooted in our personality structure. Thinking of stone age people walking about 12 miles a day, let us understand that our limited mileage of a few hundred meters today, combined with common eating habits will lead inevitably to overweight.

However, fat tissue itself must be considered as a wonder of nature that enables to store a huge amount of energy for times of famine, within a minimal space. One kilogram fat stores enough energy for about three marathons. The “problem” is that suffering from famine within western industrial societies today is rare, making it nearly impossible to exhibit a sustained decline of body fat.

Until a few hundred years ago, the conservation of an excessive intake as stored fat was an advantage in terms of selection, helping us to withstand long periods of famine. Today this predisposition is a common risk factor for cardio-vascular diseases. Elevated blood pressure and cholesterol problems are common attendant symptoms that can be observed in overweight people. In addition, degenerative joint diseases often occur as a result of the chronically increased mechanical strain.

For loosing fat a consistent reduction of energy input, accompanied by an increase in energy consumption is indispensable. To reduce body fat by 500g per week, energy intake needs to be reduced by 500kcal or by 250kcal a day if it is accompanied by an increase of energy consumption of 250kcal/d. In this context it doesn’t matter if you do modern sports like Nordic Walking (236 kcal/30min) within a special and individual “fat-burning heart rate” or if you spend the same time weeding your garden (223 kcal/ 30min).

Solely the total amount of energy is what matters. Heart rate should therefore be adapted to the available time and not the other way round. That is, if you want to spend one hour a day burning body fat, the selected heart rate should enable you to withstand the one-hour workout. Forcing a low heart rate during exercise, to stay within the so called “fat burning zone”, would result in substantially lower energy consumption!

However, if time and motivation are sufficiently available, there is nothing wrong with long training sessions and its corresponding low heart rate. Those low to moderate intensities allow for higher calorie consumption over the long term and train our metabolic system to burn fat. That is, that the involved enzyme system of our organism attune to use fat as its main energy source during exercise. Due to its nature, those kinds of training sessions are accompanied by a large expenditure of time and therefore difficult to integrate in individual’s daily routine.

Sure, depending on motivation, calorie restriction can exceed the earlier mentioned 500kcal/d. However, the daily intake should not fall below the 1200kcal threshold (mixed diet), as it would dangerously impair the mineral and vitamin supply. Therefore it is strongly recommended that diets below that level are physician controlled (1).

The composition of food is another important factor. Whereas high-carbohydrate nutrition inhibits fat oxidation, a low-carb diet will increase fat metabolism (2).

It should be kept in mind that musculature also plays an important role for an effective fat reduction as it is the second most important organ for metabolism of our body - behind the liver. It therefore substantially determines the basic metabolic rate. In addition, the repair of exercise associated muscle damage in form of micro tears causes an increased energy demand over a period of several days. Some authors even conclude that resistance training is more effective in weight management than endurance training, if both are conducted with a comparable amount and intensity (3;4).

Supplements, like L-Carnitine and others are often advertised to help burning fat. Even though robust scientific results are still missing (5), there will always be enough people buying that kind of stuff. The desire for a pill that makes hard and sweaty workouts needless is just too big.

Conclusion:

• Reducing body weight can be successful without exercise, but successful weight maintenance without regular exercise is difficult (1).
• Try to be active as often as possible: Use stairs instead of elevators, go shopping by foot, whenever possible and don't spend to much time on your couch.
• Attune volume of workout to your personal motivation and time that you want to spend. Than adjust your heart rate: Long training sessions ask for lower heart rates whereas short ones should be performed with higher heart rates.
• Resistance training should be added to your weight loss program.
• Be aware of quality and quantity of your food and avoid high carbohydrate nutrition without roughage.

Reference List:

(1) Grilo CM, Brownell KD. Interventions for Weight Management. In: Herridge M, editor. ACSM's Resource Manual for Guidelines for Exercise Testing and Prescription. 4 ed. Philadelphia, Baltimore: Lippincott Williams & Wilkins; 2001. 584-591.
(2) Jeukendrup AE. Fettverbrennung und körperliche Aktivität. Deutsche Zeitschrift für Sportmedizin 2005; 59(9):337-338.
(3) Pollock ML, Foster C, Knapp D, Rod JL, Schmidt DH. Effect of age and training on aerobic capacity and body composition of master athletes. J Appl Physiol 1987; 62(2):725-731.
(4) Klitgaard H, Mantoni M, Schiaffino S, Ausoni S, Gorza L, Laurent-Winter C et al. Function, morphology and protein expression of ageing skeletal muscle: a cross-sectional study of elderly men with different training backgrounds. Acta Physiol Scand 1990; 140(1):41-54.
(5) Jeukendrup AE, Aldred S. Fat supplementation, health, and endurance performance. Nutrition 2004; 20(7-8):678-688.