Cardio Vs Weights: Which is Better for Weight Loss

Posted by FiscusFitness, LLC on October 27, 2016

One of the most debated fitness questions is whether cardio or strength training is better for weight loss.  Duke University published a study that took on that very question. They came to the conclusion, if you want to lose weight and have to make a choice between weights or cardio, you should choose the latter.  Newspapers, online blogs and television stations all lead with the headline, "Aerobic training better than weight training for fat loss."

And why question the study?  After all, it was performed by Duke, a well respected university.  But, too many facts about the study results and study design were left out by the mainstream media... meaning you didn't get the whole story.

About the Study

A little over 200 hundred people were divided into three groups and performed resistance exercise, aerobic training or aerobics plus resistance training over an eight-month period. At the end of the study, the aerobic training group lost the most weight, weight went up slightly in the resistance training group, and the participants that did both resistance and aerobics dropped weight, but a little less than the aerobics-only group.

The Composition of Body Weight

However, it’s more than just the number on the scale that you have to pay attention to. When you lose weight, you can lose water, glycogen (the storage form of glucose), muscle, and fat. Obviously, most people want to lose fat. Despite what the headlines would lead you to believe, it was the resistance plus aerobic training group that lost the most fat, not the aerobics group. And, even though the resistance group had a slight gain in weight-- it was their lean body mass that increased… not fat.

The aerobics group lost 3.8 pounds of body weight in 8 months. Of that, 3.6 pounds was fat. The resistance plus aerobics group lost 5.36 pounds of fat and gained 1.78 pounds of muscle. That’s a loss of 3.58 pounds. Not only is that extremely close to the total net loss of the aerobics-only group, the combo group lost more fat -- while gaining muscle. Muscle is a more metabolically active tissue. It actually helps you burn slightly more calories at rest than fat. Plus, two pounds of muscle looks a lot better on someone than two pounds of fat.

Flawed Study Design?

The other problem with this research was the study design. Participants did not do the same strength training exercises. They were just supervised while completing a full body workout. A chest press is actually much different than an incline chest press even if it's still working the chest. Doing your reps at a fast tempo works different muscle fibers than a “two up, two down count.” These are all items that were not controlled.

Plus, the researchers did not put restrictions on diet. Study subjects wrote in a food diary and self-reported their intake. It is well documented, that when people try to recall what they ate 24 hours ago and estimate their portions the results are inaccurate and unreliable.  The study outcome may have been much different if diet was kept in check. 

Deciding Between Weights and Cardio

So what should you do if you have a limited amount of time to workout in your week? Participating in both forms of exercise is really best. This study really did not prove that you will lose more fat with just aerobics. Plus, there are so many other health benefits to resistance training that you should try to fit in both, even if it’s 20 minutes of aerobics and 15 minutes of strength training.

When you start an exercise program, working out can feel like a chore, but you may find as you progress that you look forward to it and are willing to carve out more time.

On the opposite end of the spectrum, if you are exercising for hours a day and your diet is not in check, you will not see results. This is a fact that people like to ignore. Until you know what you’re eating and how much, the number on the scale will never reflect what you want to see.

A final takeaway from this study is to always go to the source. Read the information yourself and ask questions. Usually there is not a one size fits all solution. People are motivated by different activities, have different genetic makeups, and respond differently to exercise. The best type of activity is one you can do (and enjoy) on a consistent basis.

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