Info taken from Mark Sisson’s Marks Daily Apple Primal Blueprint:
Grains, beans, and legumes were not readily available until we developed agriculture
roughly 10,000 years ago.
High-fructose corn syrup and vegetable oils were only made available in the last 100 years, with HFCS coming just 30 odd years ago. Today, people are fatter, more diabetic, and get more cancer and heart disease than people living 100 years ago, even if you account for differences in lifespan. Most, if not all of those illnesses are directly attributed to our poor modern lifestyles and diets.
Grains have an array of chemical defenses, including various lectins, gluten,
and phytic acid, that disrupt your digestion, cause inflammation, and prevent
you from absorbing vital nutrients and minerals. All grains contain some or all
of these anti-nutrients, to varying degrees, so when our ancestors began making
regular meals of them, their health suffered accordingly.
Starting in the early 80s, things changed. Obesity rates began a steady, constant climb until today, where almost 30% of the adult population is obese and 70% is overweight and/or obese. 1 in 3 American adults is obese. More than 2 in 3 are overweight. Does this seem right? What the heck changed? The low-fat diet craze kicked off. People were told that fat and cholesterol were killing them (based on terrible science, which I’ll get into in a future lesson) and making them fat. So, to avoid all that fat, they started eating more grains, carbs, and other processed low-fat foods.The other thing about grains (and carbs in general) is that they raise your body’s insulin levels. Insulin is required to shuttle nutrients, like carbs and protein, into various cells of the body. You eat carbs and insulin deals with them. But if you eat too many carbs – like, say, a person who was just told never to eat fat and to eat all the low-fat, high-sugar processed grain products they wanted might do – without exercising at an insane level, your body pumps too much insulin and you get insulin resistant.
When you’re insulin resistant, any amount of carbohydrate will not be tolerated. It will turn to body fat, and the more body fat you have, the more insulin resistant you get. The more insulin resistant you are, the less nutrients are being shuttled into your cells, meaning you stay hungry even though you’re eating, so you eat even more carbs that you can’t tolerate. It’s a vicious cycle, you see, and it’s led to the mess we’re in. To make things even worse, many of the carbs we’re now eating come in the form of sugar, or its cheaper, more widespread alternative, high-fructose corn syrup. Both forms of sugar are high in fructose, which the liver turns into liver glycogen, a type of carb-based energy, until its glycogen stores are full. Those glycogen stores fill up fast, and since most people aren’t using any glycogen (kinda hard to do that when you have to work an office job and sit in traffic all day), that fructose turns to liver fat.