From personal experience and extensive reading on (evolutionary) nutrition, diet and exercise, I believe that 70% of one's body composition can be attributed to diet (what you eat), 10% to genetics and 20% to exercise.
Therefore, given that you can't directly upgrade or trade in your genes yet (although epigenetics is a very exciting new field), I argue that it makes sense to focus on DIET rather than EXERCISE. Here is why:
It's a hell of a lot easier to affect change by focusing on the 70% rather than the 20%.
Let's analogize: imagine that your weight loss/body composition goal involves rowing a boat across the Hudson River.
Fat, lethargic, unhappy you sits slouched on the banks of New Jersey. You want to get to the glistening tall towers of downtown Manhattan. Your means of getting there is a rowing boat containing 10 oarsmen.
Seven are wearing racing bibs that say "DIET TEAM". Two are wearing bibs saying "EXERCISE TEAM" and one is wearing a "GENETICS GUY" bib. (Genetics Guy can't row, so if he's nice and lean and can maybe help out coxing the tempo then all the better, but if he's a big fat fatty with no voice then he's only gonna make the trip a bit slower! But don't worry about him. Most fat people blame this guy because he never objects or makes a fuss. Some people just assume this guy is a big fat, fatty because they look at their family and they all seem to be fat too and it's the easiest explanation. But if you actually met this guy you' probably notice that he's quite normal and isn't actually slowing you down so much. And no he doesn't have big bones! He hates it when you say that. Anyway just ignore him. He's just one guy out of 10 after all!)
The distance doesn't seem insurmountable... but it's a bloody long way! A good attitude helps. If you are highly motivated and optimistic it could be a relatively fast trip. However, if you aren't 100% committed to the journey then all the optimism in the world won't help. You probably won't make the journey... you may even end up further up shit creek - sorry, The Hudson!
Importantly, there is a reasonably strong current flowing against you. You are always rowing against this current, so if you stop at any time you gradually drift back towards New Jersey. Keep this in mind.
Now, if you want to reach Manhattan from New Jersey in the quickest, easiest way possible and you could hypothetically only choose ONE 'team', are you going to get the seven 'Diet' oarsmen to row, or the the two 'Exercise' guys? The exercise guys seem cool. They are all dressed up in nice expensive lycra and $200 runners. (They even brought gym bags with protein shakes and crisp copies of 'Men's Health'). But don't be fooled by the glamour - there are only TWO of them after all! Imagine how long it will take you if you just use these two Exercise guys to try and get you there. Even if you whip the hell out of these two poor guys and they work their asses off, against the current, and with the dead weight of eight dudes who aren't helping at all, you may never reach Manhattan!
No, you'd do the sensible thing and choose the 'Diet' team. Seven oarsmen trumps two oarsmen any day of the week. In fact, you don't even have to run them into the ground. Even if they put in a decent 80% effort that is sustainable, they'll slowly but surely get you to Manhattan.
Now, Ideally you would combine both teams - use all nine oarsmen and get to your goal a lot quicker. And this is obviously the best way to go about it. If both teams are particularly well in sync, and you don't have too many rests/drift-backs along the way, you will reach your goal in no time at all. But the original point remains: if you're going to focus on one "team" - for Pete's sake go with the Diet team! Exercise can be a great addition but the easier way is to focus on the 70%…. And, please, stop blaming the mute genetics guy! He's the minority!
- Clearly this is a very simplistic analogy. Diet and exercise are inextricably linked in such a way that it is difficult to affect change on one aspect without it directly influencing the other, even subconsciously. For example, if you exercise more you may find yourself eating healthier by default - food selection may change and improve in order to sustain the new activity levels.
- The inverse is also very true: if you improve your diet sensibly - say by using a Paleo template thereby providing adequate nutrition while maintaining satiety and improving health markers - you will find yourself increasing activity levels by default, if not by design as well.
- One of the major benefits I experienced when transitioning to Paleo was sustained energy levels throughout the day. No more post insulin-spike lows and sugar cravings in the afternoon. Before Paleo I would never bound up stairs without even thinking. Now I find myself doing it all the time.
- I am not saying you should ignore exercise. Quite the contrary. Exercise is so important to your overall health in many ways that extend beyond just body composition: mood, social life, sex life, cardiovascular health, stress, etc, etc. We know that. All I am arguing here is that if body composition is your goal then there is no use whipping a dead horse (or yourself in the gym on an Elliptical machine an hour a day… those things are freakin' stupid) because if you eat crap no amount of "chronic cardio" is going to help.
- Besides cleaning up your diet and exercising smartly, the other major factors that will affect your body composition are: getting enough quality sleep, managing stress, maintaining vitamin-D levels and watching overall endocrine function (hormones), and importantly, enjoying plenty of leisure and social interaction. Be smart! You are better off going out for a fun night with friends, having a few too many wines and even some suboptimal food ONCE IN A WHILE if it means that you are happy, less stressed and therefore motivated to keep healthy. Staying at home every night, eating sardines with broccoli and waking up at 6am on Saturday mornings every week to run a half-marathon is NOT HEALTHY!
My motto: "Eat Paleo. Train. Live life." - twitter.com/thepaleomodel
PS - That was a cheeky Twitter handle drop. Please follow me!