Half Their Size's Eve Guzman on Cardio vs. Weight Lifting for Weight Loss

Eve Guzman was featured in PEOPLE’s 2015 Half Their Size Issue after going from 277 lbs. to 138 lbs. by dramatically decreasing her portion sizes and sticking to a high protein, low-fat, moderate carb diet. Since her weight loss, the genetic toxicology research assistant and mom of two, 34, has coached people all over the country on how to lose weight as a certified sports nutritionist and certified personal trainer, helping them drop a combined 2,950 lbs. Guzman recently competed in a figure competition, and will be sharing the next phase of her journey in an exclusive PEOPLE blog. You can also follow her on Instagram.

There has been a huge debate since the years of Jane Fonda workouts to the new powerlifting era about what is better, cardio or weight lifting for weight loss?

Speaking from my own experience, cardio and strength training change the composition of your body in different ways. Cardio will help you drop weight and burn fat and sometimes muscle, even when we aren’t interested in losing muscle. For me, cardio left me as a smaller version of my overweight self. I used to spend 60 to 90 minutes performing cardio six days per week. I still felt flabby and was what you call “skinny-fat.”

I would wonder why other women my weight and height looked more shapely, toned and wore smaller clothing sizes. The difference was that they had muscle mass and I didn’t. My body fat percentage was still 30 percent. As I added in weight lifting, I stayed around the same weight but went from a size 8 to 2, and my body fat percentage dropped to 19 percent. My curves looked better, my arms looked more shapely and defined with less loose skin, and my waist tapered in tremendously. I obtained the #curvyfit look that I had always desired.

As for the scientific take on the cardio vs. strength training debate, Duke University recently conducted an eight-month study comparing the effectiveness of cardio only, strength training only and a mixture of both. The group who did cardio lost the most weight, the strength training only group gained a small amount of weight, and the cardio plus strength training group “improved their body composition best — losing the most fat while adding some lean mass.”

What do I personally advise to my clients? Mix ‘em: enjoy the best of both worlds. High intensity interval training (HIIT), spinning and sprinting are forms of cardio that challenge your fat burning potential and enhance lean muscle development. Twenty minutes of HIIT can help you burn twice as much fat as steady state cardio while increasing muscle mass. Spinning can burn between 400 and 600 calories per session while improving your cardio health, building lean lower body muscle, and training your abs and core. (My spin instructor @coreydiehl kicks my butt!) Sprinting with great intensity can create the same metabolic effect as weight lifting, and develops more muscle mass than long-distance running.

Here is my current workout routine:

Monday: Chest, triceps, abs and sprints

Tuesday: Legs

Wednesday: Back and biceps

Thursday: Shoulders and abs

Friday: One hour spin with Corey

Saturday: HIIT, legs and abs

Sunday: Rest day

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No matter what exercise you choose, remember that at the end of the day, food is the most important factor for weight loss. You cannot out-run a bad diet — I have tried that — but exercise is still very important.

I have maintained my weight loss for more than three years with consistent exercise five to six days per week. I’d rather spend an hour in the gym each day than in front of the television. The average American watches about five hours of television per day — you could just as easily watch Netflix or YouTube while exercising for 30 minutes on the StairMaster.

But when it comes to losing weight remember: Lose weight in the kitchen, get fit in the gym.