As paleo guru Robb Wolf puts it, think of a 100-yard football field. The first 99.5 yards are how long Homo-Sapiens spent as hunter-gatherers. As they became REALLY good at hunting and gathering our bodies adapted to that lifestyle over thousands of years. That last half-yard represents our species after the agricultural revolution, where our diet has shifted (but our genetics haven’t).

Do not step on the scale or take any body measurements for 30 days. The Whole30 is about so much more than weight loss, and to focus only on body composition means you’ll overlook all of the other dramatic, lifelong benefits this plan has to offer. So, no weighing yourself, analyzing body fat, or taking comparative measurements during your Whole30. (We do encourage you to weigh yourself before and after, so you can see one of the more tangible results of your efforts when your program is over.)
The theory is our bodies were designed, and still optimized, to eat what our Paleolithic ancestors ate. Like your hunger-gatherer forefathers, on Paleo you get all the meat from wild animals and unlimited fruits and vegetables you can eat. But no starchy vegetables (like potatoes), no legumes (like lentils or beans), no wheat, and no grains (like quinoa or corn) because those plants were invented by human beings during the agricultural revolution after our Paleolithic ancestors left the planet. You get one cheat day where you can eat whatever you want (“Occasional cheating and digressions may be just what you need to help you stick to the diet.”) No oil because it puts omega 6 and omega 3 ratios out of whack which should never exceed 2:1, except olive oil if you must. Dairy is also prohibited. And meat must come from animals that weren’t fed grains (like corn) because grains lead to inflammation and increased fat.
Kevin Hall, an obesity researcher at the National Institutes of Health who has studied low-carb diets, pointed out that the researchers used a technique called doubly labeled water to measure calorie burn before and throughout the study. This involves giving study participants a sample of water that contains (or is “labeled with”) forms of the elements deuterium and oxygen-18. Since they’re not normally found in the body, researchers can determine a person’s metabolic rate — how much energy they’re burning each day — by tracking how quickly the elements are expelled through urine sampling.
Cancer: Disease of Civilization? An anthropological and historical study by Vilhjalmur Stefansson. This classic shows what happens before and after tribes were "civilized." Covers day-to-day experience of Eskimo life. Published in 1960. Used copies are available at a steep price. To read it get it on inter-library loan. Another of his many books My Life with the Eskimo (New Edition) is available.
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.
Origins and Evolution of Human Diet was an academic web site at the University of Arkansas devoted to discussion of evolution and the human diet. They had good articles on the conferences link. Here is one from the archives: Boyd Eaton's Evolution, Diet and Health which argues that current w-6 : w-3 imbalance together with absolute dietary DHA intake quite low in human evolutionary perspective may be relevant to the frequency of unipolar depression.

Don’t even consider the possibility of a “slip.” Unless you physically tripped and your face landed in a pizza, there is no “slip.” You make a choice to eat something unhealthy. It is always a choice, so do not phrase it as if you had an accident. Commit to the program 100% for the full 30 days. Don’t give yourself an excuse to fail before you’ve even begun.
Nutrition & Physical Degeneration by Dr. Weston Price's book puts to rest a lot of myths about diet, dental, physical, and emotional health, and presents the strongest case for a super-nutritious Native (or Paleo) Diet. His book outlines the conditions/causes for exceptional health. A classic that was first published in 1938. The Soil and Health Library has a Book Review by Steve Solomon. If you don't buy the book at least read the review. N.B. If you live in one of the countries where this book is now in the public domain, you can read it online. But not if you live in a country where it is still under copyright protection.

Ketogenic diets are one of the hottest trends in wellness right now. This past year, I even wrote a keto cookbook. In fact, they have become so popular, that many variations of low carb diets are currently spearheading their way into the mainstream. While any focus on a healthier way of eating should be viewed as a positive, rather than a negative - the question remains: are carbohydrates really so bad? There is, of course - a complex scientific...
Furthermore, getting the majority of your calories from protein and fat puts you at a much higher risk for disease[citation needed]. Looking at available research will tell you that you aren't getting sick from eating bananas or potatoes but from eating high protein[citation needed], fatty foods; e.g. that McDonalds double cheeseburger[citation needed]. Human physiology is quite comparable to that of our wild primate cousins. With this in mind, looking at what chimps, for example, are eating and what we are eating, there appears a strong discord. While chimps get almost all of their calories from fruits and leaves (carbs) we tend to eat only half of our calories from carbs. This is already significantly lower and likely telling of what might be wrong. To limit carbs even further doesn't make sense, unless the carbs in question are high glycemic index ones, such as sugars.
Some fruits may contain relatively high concentrations of sugar, most are largely water and not particularly calorie-dense. Thus, in absolute terms, even sweet fruits and berries do not represent a significant source of carbohydrates in their natural form, and also typically contain a good deal of fiber which attenuates the absorption of sugar in the gut.[19]
We’re in a position to understand more of the benefits of the Paleo diet now that we have a basic understanding of which food sources are emphasized. One major benefit of the Paleo diet is an increased consumption of vitamins, minerals, antioxidants, and plant phytochemicals. Whole grains are not a good substitute for grass-produced or free-ranging meats, fruits, and veggies, as they contain no vitamin C, vitamin A, or vitamin B12. Many of the minerals and some of the B vitamins whole grains do contain are not absorbed efficiently by the body. The Paleo diet cuts out whole grains and replaces them with unprocessed, fresh foods.

A keto diet shifts your body’s fuel-burning engine from one that relies on carbs for energy to one that incinerates fat. A big benefit here is that you may lose a significant amount of weight quickly, and that can be initially motivating to see those results so quickly. The downside is that it’s a very limiting diet — you’re eating mostly sources of fat, plus a little protein, and some nonstarchy veggies — so it’s difficult to keep up, and it’s typically intended as a short-term diet, not a lifelong change.

To do the new study, Dr. Ludwig and his colleagues collaborated with Framingham State University, about 20 miles outside Boston, where they recruited overweight students, staff members and faculty members. Each participant went through two phases of the study. First, they were put on strict diets that lowered their body weight by about 12 percent, which was designed to stress their metabolisms.

The Hiwi are not particularly healthy. Compared to the Ache, a hunter–gatherer tribe in Paraguay, the Hiwi are shorter, thinner, more lethargic and less well nourished. Hiwi men and women of all ages constantly complain of hunger. Many Hiwi are heavily infected with parasitic hookworms, which burrow into the small intestine and feed on blood. And only 50 percent of Hiwi children survive beyond the age of 15.
The low-carb theory of diet is based on the relationship between blood glucose levels and the hormone insulin, and insulin's role in regulating fat storage in the human body. When one eats a meal high in carbohydrate content, blood sugar rises. In response the pancreas produces insulin. Insulin not only helps cells metabolize glucose but it also regulates the storage of fat in cells, particularly fat tissue. When insulin levels are high, fat storage is high. When insulin levels are low, stored fat is released and little new fat storage occurs. When there is no insulin (Type 1 Diabetes) there is no fat storage.
When is a low-carb diet not just a low-carb diet? When there’s a different name to it. And with the popularity of low-carb living for weight loss and health benefits, many people are turning to the diet in all its various forms. Because most Americans eat more than 200 grams (g) of carbohydrates per day, says Kelly Schmidt, RD, LDN, a nutrition consultant in Columbus, Ohio, dipping lower than that is going to be, in a form, a lower-carb diet, she notes.
The China Study is frequently cited when criticizing the Paleo Diet – focusing on a vegetarian diet and consuming rice is healthier than the Paleo Diet. I respectfully disagree with that nutritional philosophy and strongly disagree with the conclusions drawn from that book [7], and will leave you to make your own conclusions based on your own self-experimentation.
For instance, the fat allowance of the diet may be problematic. “My biggest hang-up with the paleo diet is all of the saturated fats it promotes with all of the meats,” explains Holley, noting that you could look for a locally sourced meat, whose origin and method of raising you're aware of, as a healthier option. Saturated fat from meat has been linked with an increased risk of early death. (9)