Even if eating only foods available to hunter–gatherers in the Paleolithic made sense, it would be impossible. As Christina Warinner of the University of Zurich emphasizes in her 2012 TED talk, just about every single species commonly consumed today—whether a fruit, vegetable or animal—is drastically different from its Paleolithic predecessor. In most cases, we have transformed the species we eat through artificial selection: we have bred cows, chickens and goats to provide as much meat, milk and eggs as possible and have sown seeds only from plants with the most desirable traits—with the biggest fruits, plumpest kernels, sweetest flesh and fewest natural toxins. Cabbage, broccoli, cauliflower, Brussels sprouts and kale are all different cultivars of a single species, Brassica oleracea; generation by generation, we reshaped this one plant's leaves, stems and flowers into wildly different arrangements, the same way we bred Welsh corgis, pugs, dachshunds, Saint Bernards and greyhounds out of a single wolf species. Corn was once a straggly grass known as teosinte and tomatoes were once much smaller berries. And the wild ancestors of bananas were rife with seeds.
But listen--we'd both been relatively inactive for years and each about 25 pounds overweight. Between the two of us we lost 34 lbs in 30 days and we are still going to keep up a serious commitment to Whole 30, with a few supplemental treats now and then. We feel better, we have new confidence about getting dressed in the morning, and we're more fit than in years, mostly because we have the energy to do more. The amazing thing is that you will NOT feel hungry if you hang in there and consistently prepare foods as per the cookbook/menus. There is also a very supportive and helpful forum online to supplement the book.
CrossFit is a strength and conditioning program consisting mainly of a mix of aerobic exercise, calisthenics (body weight exercises), and Olympic weightlifting. CrossFit, Inc. describes its strength and conditioning program as "constantly varied functional movements executed at high intensity across broad time and modal domains," with the stated goal of improving fitness, which it defines as "work capacity across broad time and modal domains." Hour-long classes at affiliated gyms, or "boxes", typically include a warm-up, a skill development segment, the high-intensity "workout of the day" (or WOD), and a period of individual or group stretching. Some gyms also often have a strength-focused movement prior to the WOD. Performance on each WOD is often scored and/or ranked to encourage competition and to track individual progress. Some affiliates offer additional classes, such as Olympic weightlifting, which are not centered around a WOD.