Science Summary: Weight Loss and Strength Training

The Best Weight Loss Plan

A quick Google search for “best weight loss plan” will give you approximately 7 trillion results written by everyone who has ever set foot inside a gym (just a ballpark here).  Not to discredit these people, whatever they did worked for them.  That doesn’t mean it will work for you though.  There’s a reason researchers use large groups of people and only test one or two things at a time, it controls for all the other stuff out there influencing the results.  At the end of the day, the “best” weight loss plan is one that is proven to work under these conditions.

Diet And Exercise

In this post, I’m going to be looking at a study that compared how exercise influenced weight loss while on a diet.  You can find that study here.  It’s an accepted fact that in order to lose weight, you need to eat less (for more on this and resources check out our page on weight loss).  Beyond that, we get into all sorts of debate about which type exercise is the best for losing weight.  Some argue you need lots of cardio, others say sprint training is the way to go.  At Catalyst, we say you need to lift heavy and this study is one of the reasons why.

In this study, the researchers divided participants up into four groups: one control; one on a diet (D); one on a diet and cardio program (DE); and one on a diet, cardio program, and strength training program (DES).  Diet parameters were the same for all participants and both exercise programs were done three times per week.

What They Found


After the study, the researchers observed that all participants lost roughly the same percentage of body mass.  The people who were strength training lost much more of this mass from fat stores though.  In the diet only group, about 31% of weight lost came from lean body mass (muscle).  This was limited to 3% in the strength training group.

What It Means To You

Muscle mass is one of the biggest factors in your body’s metabolism.  The more muscle you have, the more energy your body burns at rest.  Beyond that, bigger and stronger muscles let you up the intensity during you workout which means burning more calories.  From a general health perspective, more muscle mass is correlated with decreased rates of injury (especially in older populations) and higher quality of life across the board.

From the aesthetic side, muscle mass is what gives you that toned look everyone wants.  Without muscle mass, fat loss results in the “skinny fat” phenomenon where you might weigh less but still lack the definition you were hoping for.

The moral of the story here is that you want to maintain muscle mass while dieting and lifting weights is an essential part of that.