I often get resistance, pun intended, when I talk about resistance training (also known as weight training) for losing fat. There are a lot of people that believe you should only do cardio to lose fat. That simply is not true. I am going to summarize a few studies that have been published over the years to prove my point.
Here’s a little background first. As people age, generally they lose muscle mass, lose strength, increase fat mass, and their overall metabolism slows down. This is mostly due to being less active than when they were younger. Resistance training can slow this process down or keep you feeling younger, much longer.
Ryan, A. S., Pratley, R. E., Elahi, D., & Goldberg, A. P. (1995). Resistive training increases fat-free mass and maintains RMR despite weight loss in postmenopausal women. Journal of Applied Physiology,79(3), 818-823. doi:10.1152/jappl.19220.127.116.118
In this study, the subject group was healthy, untrained, postmenopausal women. They were divided into resistance training (RT) alone and resistance training with weight loss (RTWL) groups. After 16 weeks of resistance training, both groups increased fat free mass (muscle), increased strength, and an increase in resting metabolic rate (RMR). The RTWL group that had also saw a decrease in fat mass and body fat percentage. The conclusion was that resistance training is a valuable component to weight management in postmenopausal women.
Treuth, M. S., Ryan, A. S., Pratley, R. E., Rubin, M. A., Miller, J. P., Nicklas, B. J., . . . Hurley, B. F. (1994). Effects of strength training on total and regional body composition in older men. Journal of Applied Physiology,77(2), 614-620. doi:10.1152/jappl.1918.104.22.1684
This study looked at 16 weeks of resistance training with healthy, untrained older men (60+). The men were divided into 2 groups: a control group that did nothing, and a group that did resistance training. The RT group saw decreases in fat mass, increases in muscle mass, and increases in strength.
Demling, R. H., & Desanti, L. (2000). Effect of a Hypocaloric Diet, Increased Protein Intake and Resistance Training on Lean Mass Gains and Fat Mass Loss in Overweight Police Officers. Annals of Nutrition and Metabolism,44(1), 21-29. doi:10.1159/000012817
Another study looking at police officers, divided them into 3 groups:
- 12 weeks RT, hypocaloric diet (80% of needs)
- 12 weeks RT, hypocaloric diet + high protein using casein protein supplement
- 12 weeks RT, hypocaloric diet + high protein using why protein supplement
All 3 groups lost fat mass. The 2 groups with high protein diets were the only ones to see increases in strength and lean mass (muscle mass gain). This would suggest that strength training while restricting calorie intake will preserve the muscle mass you have, but you will not see any gains in strength or lean mass. If you increase your protein intake while restricting calories, you can still gain muscle, lose fat, and increase strength.
My 2 cents:
In order to be successful at changing your body, you need to change your diet and do resistance training. You must increase your protein intake either through the foods you eat or supplementing.
Notice how none of these studies mentioned cardio? Yeah, you don’t have to go for a run to look and feel better. In fact, doing cardio for hours may negate any progress in attempts to gain muscle and strength. Look at long distance runners, they have some muscle, but they are very thin and lightweight. Their training primarily focuses on type 1 (slow twitch) muscles. These muscles don’t get very big, they don’t produce as much force but are more resistant to fatigue. Long duration, moderate intensity cardio can burn more calories per workout, but does not burn more calories after the workout is over.
Resistance training trains your type 2 (fast twitch) muscles. These muscles produce more force and are capable of getting bigger in size compared to type 1. This will increase your resting metabolic rate, giving you more wiggle room in your diet and sets you up for better long term success. Resistance training also causes small trauma to your muscles, and your body has to spend calories while you rest to repair and grow bigger muscles. You can do cardio that trains your type 2 muscle fibers, that would fall under interval training. Interval training raises your metabolism for hours after you are done, depending on how intense it was. Click here for more info on that.
Some sports would fall under interval training: soccer, football, mountain biking (climb up the hill, bomb down the hill), basketball, lacrosse, hockey. You can also do it by alternating intense work, followed by periods of moderate to light work on an exercise bike, treadmill, or rower for example.
Snyder, Ka, Je Donnelly, Dj Jabobsen, G. Hertner, and Jm Jakicic. “The Effects of Long-term, Moderate Intensity, Intermittent Exercise on Aerobic Capacity, Body Composition, Blood Lipids, Insulin and Glucose in Overweight Females.” International Journal of Obesity 21.12 (1997): 1180-189. Print.
In this study, moderately obese women were instructed to do 30 minutes of moderate intensity cardio for 5 days per week, for 32 weeks. The group data at the end of 32 WEEKS showed no statistically significant changes for aerobic capacity, body composition, weight, insulin, glucose, or lipid profile. Wouldn’t you be frustrated if you committed to do something for 32 weeks and it didn’t work for losing body fat? I would be pretty bummed. In the above mentioned resistance training studies, statistically significant improvements were seen in body fat, lean mass, and strength in half the time.
Irving, Brian A., Christopher K. Davis, David W. Brock, Judy Y. Weltman, Damon Swift, Eugene J. Barrett, Glenn A. Gaesser, and Arthur Weltman. “Effect of Exercise Training Intensity on Abdominal Visceral Fat and Body Composition.” Medicine & Science in Sports & Exercise 40.11 (2008): 1863-872. Print.
In this study, middle-aged, obese women with metabolic syndrome were divided into 3 groups: a control group that maintained their current physical activity levels, a low intensity exercise group, and a high intensity exercise group. There was no diet intervention. After 16 weeks, only the high intensity group had statistically significant changes in abdominal subcutaneous (under the skin) fat and visceral (around the internal organs) fat.
So basically, if you want to transform your body, do resistance training, interval training, and change your diet.