The effect of eating carbs strategically is simple. Any carbs consumed raise your insulin level which normally leads to increased energy levels or storing fat. Here is a short video in which Jennifer Elliott, an Australian dietitian, explains such effects of insulin. However, post-workout carbs may have an anabolic effect and stimulate muscle growth (depending on the workout and intensity). This doesn't mean that you need to eat carbs if you want to gain muscles. Unless you aim for a significant muscle gain, post-workout carbs are not needed.
Ive noticed since having 1-2 days a week higher in carbs (150g-200g) has actually helped me lose weight. I was starting to plateau after about 4 months eating 90% primal. I added in some sweet potato, or other sharchy root (beets) and bam!! My weight loss continues! Ive even noticed eating 100-150g of naturally sourced carbohydrates (potatos, fruit) dont really have much affect on my anymore. When I eat any grain however, i bloat up like a baloon. Id reccomend a 1-2 day refeed for those who are struggling with the last few lbs! definitely! great article!