The paleo diet is more formally known as the paleolithic diet due to the idea of returning to foods which may have been consumed during the Paleolithic era (roughly 2,500,000 years ago to 10,000 BC). Other names include Stone Age diet, hunter-gatherer diet, and caveman diet. Lean meats, fish, fruits, veggies, nuts, and seeds get a pass while excluding dairy, grains, and legumes (pod plants such as peas, peanuts, beans, and lentils). While it may sound complicated, the idea is to stick to stuff before farming became a thing. The paleo dieters formally advocate the discordance hypothesis - human genetics do not align with the modern diet birthed from farming practices. While a larger audience may find the exclusion of refined sugar, salt, and highly processed food ideal, a possible downside comes with the avoidance of dairy.
Can additions such as marinade and seasoning be used? The answer is yes as long as it isn't made with "junky stuff." There has even been niche marketing utilized such as 'paleo powder.'
How do paleo dieters aka prehistoric men obtain calcium and vitamin d? The solution is lots of leafy greens, shellfish, bone-in fish, and cod liver oil. Don't be suprised if that doesn't sound appealing even to the die-hards, as it is common to find a 50% definciency within their regimen.
The paleo diet is like other fad diets when it comes to inspiring an ideology and lifestyle. Estimates show a paleo market at over $2.5 billion in the US, and expectations to grow considerably over the next decade. No one can pinpoint the future, but it may look something like this: