Ello. I've been reading more and more about the Paleo diet through websites, blogs and journals. Something that crossed my mind was the 80/20 rule. So, I would really appreciate it if someone would elaborate on that rule. PLEASE and THANK YOU! looking forward to your answers!
I think this rule is best interpreted as strive for 100% - but if you slip up every once in a while don't beat yourself up over it!
'Pareto principle' from an Italian man named Vilfredo Pareto.
He observed that in Italy 80% of the land was owned by 20% of the people, and that 20% of the peas pods he was growing contained 80% of his harvested peas. Then economists picked up on this and called the principle the 'Pareto principle' as this same principle appears to exist all over the place. 80% of sales come from 20% of customers, 20% of people in the world own 80% of the worlds wealth.
I actually first came across it practically with Tim Ferris who keeps hammering on that 80% of your benefits come from 20% of your efforts. Eating, weightlifting, time-management, relationships and even sex if I remember.
So it is not so much that you should aim for 80% (or 100%) but rather that the majority of the benefits from your diet and lifestyle change 'may' likely come from 20% of your efforts.
While looking for more examples I came across this: http://www.lifehack.org/articles/productivity/the-top-4-misapplications-of-the-8020-rule.html
Basically that if you follow the diet 80% of the time you'll get 95% of the benefits. There are some caveats however, most notably for those who are gluten intolerant. Those people need to strictly avoid gluten, however some ice cream may be okay, for example.
To me, the 80/20 rule is meant to ease CW people early in their transition onto paleo, so that you don't make the lifestyle an all or nothing thing and then give up before any results are achieved. However, following it at 80% is, in theory, enough to attain benefits which should convince you that striving for that 100% is a worthy goal. (One that your body will appreciate.)
I started following the 80/20 rule when I first went Primal in August 2010. That lasted 4 months and I then went 100% Paleo. For me 80/20 meant I ate Primal all week, had one cheat meal and cheat dessert once a week. I would get so sick after my cheat meal that I finally listened to my body and went 100%. I stayed 100% for 6 months, then tried some gluten free treats or gluten free pizza. That also made me sick. I function best @ 100%.
Follow up question: Say you follow a 95/5 version of the Pareto principle but the final 5 is really bad, to what extent are you undermining your progress? In particular, eating Paleo is super easy at work and home. But, when I go out once per week (at very most) you're talking classic SAD. Beer, sandwiches, pasta, etc. I definitely feel worse after having eaten in such a manner, but I'm hesitant to miss out on things. I'm amazed at the extent to which people resort to their "healthy" bagels and pasta while also complaining about their unlosable weight.
I think both versions of 80/20 are at play in a paleo lifestyle. 80/20 as applied to compliance is more along the lines of the other responses ... i.e., you are unlikely to see useful benefits by eating SAD 80% of the time and paleo 20%.
But the Pareto is also at play too, more along the lines of what Keith Norris talks about regarding performance vs health: 20% of your effort gets you 80% of the benefit of health and after that, you expend a lot of work for far less benefit proportionally, in fact, it can be detrimental:
Hack my first day on Paleo 4 Answers