The Paleo diet is a close cousin to the Low Carb diet. The Paleo and Low Carb diets are both elimination diets (they say to not eat particular things) and many of the things that they eliminate are in common.
The Paleo diet is based on the idea that our genetics were formed in the Paleolithic Period. This is the time period before agriculture. Man was largely a hunter/gatherer in our long developing history. Thus, the Paleo diet eliminates grains since they are largely the product of agriculture. The Low Carb diet also eliminates grains but it is because they are concentrated forms of carbohydrates.
Paleo as a Philosophy
Paleo is based on an ancestral/evolutionary philosophy. The idea is that man has developed over millions of years. Natural selection is the process which has eliminated and honed man down to the specific biological machines that we are. Eating food which was consistent with what we ate over that long period makes more sense than eating Fruit Loops.
The Biblical story is often placed in contrast to this point of view. In the Bible Adam and Eve are placed into a garden to tend the garden. There are indications in the text that the original order was not consuming animal products. After the flood story man is told Noah is to eat animals.
The human earliest conflict in the Bible is between the brothers Cain and Abel – farmer and a herdsman. The farmer brings a sacrifice from his crops and God is displeased. The herdsman slaughters an animal and his sacrifice pleases God. Thus, the evidence in the Bible is that both are very early modes.
For either the evolutionary or Biblical view, processed food is very recent in our history. We are not well adapted to these processed foods. Eating natural foods fits well into either paradigm. The wheat/bread in Bible times is not like our flour/Wonder Bread products of today. The refining process eliminates protective elements, like fiber, from the raw food.
Refining/processing concentrates carbohydrates into a more dense form. Imagine something like fudge in nature – you can’t find an equivalent thing. The only really sweet things in nature, like honey are pretty well protected. Even sugar cane is fairly low in sugar. It’s when it is processed into powder form that it becomes dense and separated from fiber.
Studies have been done which show good results with Paleo diets (Tommy Jönsson. A Paleolithic diet confers higher insulin sensitivity, lower C-reactive protein and lower blood pressure than a cereal-based diet in domestic pigs. Nutrition & Metabolism, 2006;Nov 2, v3.1, p 39).
This study in domestic pigs suggests that a Paleolithic diet conferred higher insulin sensitivity, lower C-reactive protein and lower blood pressure when compared to a cereal based diet.
Not that we want skinny pigs.
The issue of life expectancy is given as an argument against the Paleo diet. After all cavemen, they say, died at early ages. Much of the reason for early death is due to accident or bacterial infection. There is evidence that there was very little heart disease in our Paleolithic ancestors.
Storage in Man vs Storage in Structures
Man has a very limited ability to store carbohydrates directly in the body. We store dietary carbohydrates in the form of glycogen which we have about a day’s worth of stores. Excessive protein, carbohydrates and fat get stored in our body which can take us through many weeks/months of food shortage. It is rare in our world to face extended shortages of food. Even our poor are rarely hungry.
Animal products are quickly perishable and refrigeration is a relatively new invention which extends this time. Carbohydrates, in the form of grains, can be stored for very long times.
It is interesting that the ability of our bodies to store food is the opposite of the storage capabilities of food. After agriculture came into prominence, wheat got more people through famines.
Dairy is a Difference
Paleo typically doesn’t include dairy products (THE PLACE OF DAIRY ON A PALEO DIET). Low Carb diets typically include dairy although some people find the high fat nature of dairy products can slow weight loss.
Fruit is a Difference
The Paleo diet includes fruit. A possible criticism of some implementations of the Paleo diet is that Paleolithic man would have only had access to fruit in short seasons and in limited forms. It is noteworthy that the more north the less fruits are available both in variety and season length.
My raspberry bush produces black raspberries every year. The entire plant provides a very limited number of berries. I can’t practically access most of the berries since the plant has barbs that protect many of the berries. For some reason bugs don’t bother the plant. I eat the berries when they come in season and I will eat all of the berries I can harvest from my one very large plant. I eat them every day or two. It’s not all that many grams of carbs total and they taste great. But the season when the berries are there is really short here in SW PA. There’s large seeds in the berries and probably a good amount of fiber. It takes 4 ozs of the berries to get 17g of carbohydrates and I never get anywhere near that much in a single day (Nutritional Value of Black Raspberries). I don’t know if this is a natural plant or one that someone deliberately planted in the past. It’s in the corner of my backyard.
The exception to seasonal limits may be tropical regions where food like bananas have been more widely available over wider time frames (Banana Tree Harvesting – Learn How And When To Pick Bananas). To make the point though, bananas just entered the North American diet after the Civil War (Wikipedia). It hasn’t been long in terms of our history that we could get bananas any day of the week and for a couple of pounds per dollar and bananas certainly weren’t a part of my own Northern European ancestry.
The Low Carb diet eliminates nearly all fruit due to the high carbohydrate load. There is no accommodation for seasonality in Low Carb.
Paleo/Low Carb Hybrid
Both sides have learned from each other. It is possible to eat Low Glycemic foods on Paleo. The Low Carb community has taken some of the criticisms about excess fat consumption from the Paleo community. Some Low Carb folks have found dairy to be problematic and adopted a hybrid approach to their diet.