Advocates of the diet argue that the increase in diseases of affluence after the dawn of agriculture was caused by changes in diet, but others have countered that it may be that pre-agricultural hunter-gatherers did not suffer from the diseases of affluence because they did not live long enough to develop them.[29] Based on the data from hunter-gatherer populations still in existence, it is estimated that at age 15, life expectancy was an additional 39 years, for a total expected age of 54 years.[30] At age 45, it is estimated that average life expectancy was an additional 19 years, for a total expected age of 64 years.[31][32] That is to say, in such societies, most deaths occurred in childhood or young adulthood; thus, the population of elderly – and the prevalence of diseases of affluence – was much reduced. Excessive food energy intake relative to energy expended, rather than the consumption of specific foods, is more likely to underlie the diseases of affluence. "The health concerns of the industrial world, where calorie-packed foods are readily available, stem not from deviations from a specific diet but from an imbalance between the energy humans consume and the energy humans spend."[33]
The Whole30 is not a diet, a weight-loss plan or quick fix – it’s designed to “change your life,” the founders say, by eliminating cravings, rebalancing hormones, curing digestive issues, improving medical conditions and boosting energy and immune function. The theory behind it is that all sorts of physical and mental health issues – ranging from acne to depression to allergies – could be due to your diet. But you can’t know which foods are to blame for what ails you unless you cut out all traces of sugar, alcohol, grains, dairy and legumes for 30 days. By day 31, you’ll be free from your food fog and may not even miss your nightly wine ritual or morning muffin fix. If and when you reintroduce food groups, your body’s reaction will tell you which foods you should continue to avoid – or at least limit.
The main benefit of Whole30 though is to see how certain food groups affect your body. If you normally eat everything, you'll never really know if dairy may be making you bloated or if grains may be upsetting your stomach. By cutting out most of the food groups and processed foods for 30 days and slowly reintroducing them into your diet, you'll be able to spot which foods are doing what to your body. 
While there is wide variability in the way the paleo diet is interpreted,[6] the diet typically includes vegetables, fruits, nuts, roots, and meat and typically excludes foods such as dairy products, grains, sugar, legumes, processed oils, salt, alcohol, or coffee.[1][additional citation(s) needed] The diet is based on avoiding not just processed foods, but rather the foods that humans began eating after the Neolithic Revolution when humans transitioned from hunter-gatherer lifestyles to settled agriculture.[3] The ideas behind the diet can be traced to Walter Voegtlin,[7]:38 and were popularized in the best-selling books of Loren Cordain.[8]
Meetup has a growing number of paleo groups, now numbering in the dozens. Each has a local message board. They have a map of Paleo Diet Meetups around the world. Initially I tried listing them all here. The number grew and Meetup wasn't letting me find groups in newest order, except for my zip code. You now have to go there to find the one nearest you.
Instead, introduce one new food every three days, since food sensitivities can take up to three days to show symptoms, and write down how you're feeling each day. "Keep portions small and enjoy new foods along with the old foods that were allowed," says Shapiro. "Remind yourself to start slow – you can now eat these foods regularly so there is no need to overindulge."
A metaresearch group at Tilburg University in the Netherlands investigates scientists’ research methods and operations, scrutinizing questionable practices such as selective reporting of statistical tests and data massaging. The group instead advocates for practices such as preregistering studies and making experimental data immediately available for open external review and verification. Its members are optimistic that “the perverse incentives of careerist academia, to hoard data and sacrifice rigor for headline-generating findings, will ultimately be fixed.”