Short answer:
Yes, I suggest you finish the 5K before you transition to a primal diet. In fact, try to block out a few weeks to transition to primal during a time where you're not making important decisions, operating heavy machinery or making other significant life changes. I'm not joking. The low-carb flu can be very disruptive for a short time but after that it's SOOOOO worth it! I also suggest that when you're ready to switch you commit to a full 30-day trial.
Long answer:
I've shared this before, but here it is again:
For more info on the Primal Blueprint go here --
http://www.marksdailyapple.com/definitive-guide-primal-blueprint
For more than a decade prior to 2011 we had been following Dr. Andrew Weil's diet advice: avoid processed foods, focus on organics, mostly vegetarian, lots of whole grains, low to moderate fat intake. Really healthy, right? During that time I could lose weight whenever I wanted by counting and restricting calories, but I'd slowly gain it back as soon as I stopped logging my foods.
Come Jan 2011 I had put on some weight after a long, stressful project at work. It was time to start logging and restricting calories again so I could lose the extra pounds. Since I was going to focus on my eating habits anyway I decided this would be a good time to experiment with a primal diet. I had been reading about it and was curious. The plan was to try it for a month not restricting calories, keep an eye on my cholesterol levels, body fat and weight, and then switch back to my usual diet and count calories to lose weight.
Well, it's been over a year and a half and I'm still eating a primal diet. The first few weeks were tough for me with the low-carb flu but everything after that has been a breeze. By the end of my one month trial my results were so stunning that my husband decided to give it a try. He quickly became a convert, too. After I got past the low-carb flu my appetite and hunger cues changed so significantly that it was easy to lose weight without even trying. I dropped 20 pounds in the first 3 months, haven't gained back a pound and haven't had to plan or log my meals to lose or maintain. I never get that "shaky" hungry feeling I used to get. I feel way more satisfied after a primal meal than I ever did on my previous diet. I don't get food cravings the way I used to. I literally can eat all I want of really delicious, rich, filling foods and still lose weight. I know it sounds too good to be true but it's no lie.
Another interesting thing is that I now eat MORE vegetables on a primal diet than I did when I was eating a mostly vegetarian diet. I traded in my grains for a mix of meat and more veggies, so it's a net increase in veggies from my previous eating. And I went from typically getting <30% of my calories from fat to getting >50% of my calories from fat, but my lipid panel improved in all areas (lower total cholesterol, lower LDL, higher HDL, lower triglycerides). The same is all true for my husband.
Here's a picture of us from last month (June 2012).
Both my husband and I continue to maintain/lose weight, improve muscle tone, feel great, have more energy and improve our overall health. And we manage all of this without any special planning, meal logging or use of will-power. With my previous eating habits I would certainly gain weight if I went on vacation or went on a business trip or worked through a period of long hours for a stressful project at work. Well, over the last year I've done all of those things without gaining a pound without any effort and without feeling deprived.
I can't say this is the right eating plan for everyone nor that everyone will have similar results. It's certainly worth a 30-day experiment to see if it's right for you. Oh, and you may be one of the lucky ones like my husband and only have a mild case of the low-carb flu lasting a day or two. But it's best if you prepare yourself for a case like mine that lasts a couple of weeks during which time you get a ticket for running a red light. (Red light? There was a red light there?)
Good luck with the 5K and with your diet changes!
Peace,
Karen