By Desmond Lew, MD
It’s a well known fact that obesity is associated with Type II diabetes. The American Academy of Pediatrics has recommended increased physical activity as the primary method to improve obesity and obesity related illnesses in children.
There are many studies that show that aerobic and resistance (muscle) training improve abdominal fat distribution, liver fat content, and increased sensitivity to insulin in the liver and the muscles. There has been no studies just looking at only muscle training on insulin sensitivity in teens until recently. In the November journal of Medicine and Science in Sports and Exercise®, a group of researcher examined the effect of resistance training in a small group of obese non-diabetic hispanic teens.
The average age of the teens was 15 years old, average BMI was 35, and 40% body fat; they were put through a 12-week resistance training program exercising all major muscle groups twice a week for one hour each session. At the beginning of the study and completion of the study their total body fat and liver fat was measured by MRI, insulin sensitivity at the muscles and liver were also measured.
Muscle training may be more attractive to obese teens because aerobic exercise tends to be more difficult and increased muscle mass and tone provide greater positive feedback. It was hypothesized that increased muscle mass will decrease muscle fat, liver fat, visceral fat and improve insulin sensitivity.
The results of the study showed improved muscle strength, no change in daily caloric intake (2853 cal/day), and total body fat did not change but lean body mass did increase. The liver and muscle fat content did not change. Insulin sensitivity in the muscles did not improve, but liver sensitivity did improve by 24%.
Previous studies have shown that an equivalent amount of aerobic exercise decrease total body fat and increase insulin sensitivity in the muscle and liver by a greater amount than this simply muscle resistance from this study. It’s not clear why only liver sensitivity to insulin was only increased since there was no decrease in liver fat. However it is clear that aerobic and resistance exercise combined have the most benefit.
A home exercise program that is simple and does not require a great deal of specialized equipment is the P90X DVD exercise and diet program. This is not for the faint of heart and there are easier programs available but if your teen can stick to this program, the results can be amazing. I have done this program and can attest to it’s results. The P90X system is a great overall workout program, it has a great mix of aerobic and resistance exercises and is cheaper than a gym membership. Be sure to speak to your physician before starting this or any exercise program.