The other are right that say it has more to do with body composition than it does with only muscle or fat mass.
It also has to do with genetics.
Northmen will rarely, if ever, be able to get ripped. Genetically, they carry more fat, and I think everyone can guess the reason. When you see northern bodybuilders, I hate to say it, but when they're ripped, they took 'roids to do it, and I don't care how tall the stack of bibles is that they swear on that they are clean.
Likewise, it's very, very hard for someone from an equatorial genetic background to put on a lot of muscle or fat.
When I was in college and lifting competitively, being an engineering student I had a compulsion to graph everything. We found the optimum power to weight ration (ability to lift a certain poundage at a given bodyweight) turned out to be when the person was at approximately 12.5% bodyfat. The next thing we found out is that the fatter they got, the stronger they got, but after the optimum ratio was reached, they may only gain 1-2% lifting ability for every 8-10% bodyfat. The other thing is the ripped guys were WEAK. Once they dropped below 9-10% body fat they lost strength FAST. THis is why you don't see ripped powerlifters, and bodybuilders put on fat to train in the off season.
Being ripped, to bodybuilder standards, is also an unnatural, dangerous thing. These guys 'roid up, eat nothing but protein for weeks before an event and severely dehydrate themselves (to make the skin thinner) before competing. You'll often have seve3ral die behind the stages every year.
So, being ripped, with a lot of muscle means you aren't in a good position to survive. But it's not because of your muscle mass, it's because of everything else you did to get ripped.
On the other hand, being a chicken-legged weakling has no benefit, either, unless you live on the African plains, and don't have to have much for shelter and need to go without eating for days at a time.
What it comes down to, is eat sensibly, exercise well, and lie with what you get. Your body will quickly adapt to the situation, and then will fight you tooth and nail from there.
Example. A while back, I completely revamped my diet and exercise. I dropped 35 pounds in 4 months, and STOPPED. My doctor wanted me to lose more weight. So I dropped from the 2000 Cal a day diet I was on to a 1200 Cal a day diet, but no exercise. I dropped another 5 pounds. The last 4 months I'e kept the 1200 Cal diet, but went to hiking a 6 mile trail 4 times a week with a pack, and started lifting weights as well as doing my manual yard work (mow with an old spool mower, cut wood with an axe, clear thorns and brush with my 3 pound kukri). I dropped another pant size. Went to the doctor expecting to kick ass. What happened? I have gained 7 pounds. Yeah, I lost fat (evidenced by the drop in pant size, and I can wear a XXL shirt instead of a XXXL), but put on a lot of muscle. When my doctor saw it, she did her exam (to include my yearly physical), and told me that she can see my abs and pecs (not ripped), I don't have a gut or love handles pouring over my belt. Unless I severely catabolize a lot of muscle, or get cancer, I'm probably not going to lose anymore weight, no matter what I do.
So stop looking at bodybuilding mags, Glamour mag, artificial people on TV, etc. Be sensible and let your body find its preferred equilibrium point and just live with it. Being a "fashionista" isn't worth the trouble.