Skinny but not fit? Fitness coach reveals why low body fat doesn't guarantee a toned body, despite consistent workouts

In a recent Instagram post, fitness coach and nutrition PhD Joseph Munoz addresses what he calls one of the most baffling fitness states: being “skinny fat.” With a strikingly simple caption — “Skinny fat isn’t a weight problem. It’s a muscle problem” — Munoz throws a wrench into traditional fat-loss thinking.

“You’re not overweight,” Munoz says. “You just don’t look like you work out.”

That’s the paradox — despite being at a healthy or even low body weight, some people still struggle with undefined arms, flat glutes, and a lack of visible tone. This isn't about obesity or excess fat, Munoz emphasizes. It's about having too little muscle.

Cardio Overkill and Calorie Confusion
According to Munoz, the confusion worsens when people double down on cardio and drastically cut calories. “The more you exercise and the less you eat, the worse the problem seems to get,” he explains in the viral video. The issue isn’t about trimming down fat, but about failing to build up the muscle that shapes the body.

As he puts it, “Most people just focus on weight loss instead of building a body that they actually love.”

That focus often leads to muscle loss alongside fat reduction — meaning your physique remains untoned even if you technically weigh less.


Rethinking the Workout and the Diet
So what’s the fix? Munoz says the solution lies in switching your focus: from simply burning calories to building strength. Instead of endless cardio sessions, he recommends resistance training as the primary workout approach — a method that promotes muscle growth and better body composition.

And when it comes to food, he advises people to stop starving their bodies. “Focus on actually eating more of the right foods that fuel your performance and support recovery and muscle growth,” he says.

For those obsessed with the scale, Munoz urges a shift in mindset: “Focus on how your body feels and your performance in the gym.”

So the next time you look in the mirror and wonder why all your hard work isn’t translating into visible results, consider that the issue might not be fat at all. It might be what’s missing underneath — and that missing piece, says Munoz, is muscle.