Dr. Squat - Dr. Fred Hatfield

Redman LM, Heilbronn LK, Martin CK, Alfonso A, Smith SR, Ravussin E.
Effect of calorie restriction with or without exercise on body composition and fat distribution.
J Clin Endocrinol Metab. 2007 Jan 2

A recent study was published in the Journal of Clinical Endocrinology and compared the difference in fat loss between an aerobic exercise plus diet group to dieting alone.

The exercise protocol called for 5 sessions per week of aerobic exercise - averaging 50 mins per workout for 24 weeks.

The exercise group did not lose any additional weight or fat mass than the diet only group.

This is consistent with earlier research findings looking at aerobic exercise (when actually added in addition to dietary restriction) and its influence on fat loss (as I wrote about in Real World Fat Loss).

I do want to add though, that studies using interval training and resistance training interventions have shown an additional fat loss effect with these types of higher intensity exercise. The underlying mechanism as to why that is, still appears to be EPOC related. Higher intensity work such as resistance training causes metabolic disturbance - and the body burns more calories the rest of the day as a result. This creates a bigger deficit than a lower intensity intervention.

The take home message is once again -- steady state aerobic exercise appears to contribute nothing to fat loss over caloric restriction alone. A good fat loss program should include some form of caloric restriction, resistance training and some higher intensity cardiovascular work to create a caloric deficit and ramp up metabolic demand.

I also think 'steady state' needs to be defined. In cycling and running terms, steady state is a VERY INTENSE level right under anaerobic threshold and in cycling is used as training for time trials and/or breakaways. For me I did steady state with a heart rate of 150-160 BPM. Trust me, at that intensity you WILL be burning lots of fat.

The problem with these studies is the aerobic level is at such an easy level that nothing really occurs. In their terms, 'steady state' probably means 'really easy'.