What is paleo?
The Paleolithic diet is not a “diet” in the count-every-calorie-I-hate-my-life sense. It is a lifestyle that encourages us to eat and live the way that our ancestors did for hundreds of thousands of years. The first homo sapiens appeared on earth 200,000 years ago. They hunted and gathered, slept, made shelter, and occasionally ran for their lives. They were strong and healthy and didn’t suffer from the diseases that we do now. The agricultural revolution changed the way we modern homo sapiens eat 10,000 years ago. Meaning, we have only been eating wheat and other grains and domesticated animal products for 10,000 years out of our 200,000 year existence. The paleo diet is the avoidance of all grains (even whole grains), refined sugar, legumes, and dairy products. It is eating vegetables, meat, poultry, fish, nuts, and fruit. The paleo lifestyle is to exercise the way we used to: lots of movement, like walking, some heavy lifting, and some sprinting. Our ancestors did not read magazines for two hours on the elliptical or run marathons.
What to eat
Fruit and veg: Go crazy for veggies. Make them the base of your diet and you can’t go wrong. For people trying to lose weight, reduce fruit and starchy vegetables like potatoes, beets, winter squash, and root veggies. For maintaining weight, gaining weight, and sustaining heavy exercise, use starchy vegetables and fruit as your carbohydrate source.
Nuts and oils: Any nut is fair game except for peanuts, which are technically legumes. Monounsaturated fat is good for us, while polyunsaturated fat is more complicated. Polyunsaturated fat is divided between omega 3s and omega 6s. While we do need omega 6s, the ratio of omega 3 to 6 should be 1:1. Modern diets are 1:10, which increases our risk of heart disease. We should emphasize omega 3s and reduce omega 6s.
- Monounsaturated oils include: nuts, avocados, olives and olive oil, fish, cod liver oil, grass fed meats, and plants (which obviously don’t have that much fat)
- Polyunsaturated omega 6 sources include: corn, soy, cottonseed, grapeseed, sunflower, safflower and other vegetable oils, and grains
- Polyunsaturated omega 3 sources include: salmon, sardines, fish, walnuts, flax, hemp, nuts, grass fed meat, pasture raised chicken & eggs
Meat: meat should ideally be grass fed and organic. Grass fed meat is naturally leaner and contains increased levels of omega 3 fats and decreased levels of omega 6 fats compared to grain fed animals. This is good because omega 3s are anti-inflammatory where as omega 6 fats are pro-inflammatory (bad!). Post-agricultural revolution, cattle began being grain-fed because it is cheaper and they get fatter. If you can’t afford grass fed meat, go for the leanest cuts of conventional meat and supplement with other forms of healthy fat, like avocados, nuts, olive oil and coconut oil. Avoid vegetable oils, as they are high in omega 6.
Poultry and fish: Poultry and eggs should ideally be free-range and not fed a “vegetarian” diet, which really just means corn and soy. Again, this is so that the fat content of the meat and eggs is higher in the fats that reduce CVD. Fish should ideally be wild caught because farm-raised fish are fed (surprise!) corn and grain feed. Remember, the reason that corn and grain fed animals and fish are less healthy than their naturally grazing counterparts is their fat content. Naturally grazing species will have a more anti-inflammatory omega 3 fats and less inflammatory (and thus CVD inducing) omega 6 fats.
About red meat and saturated fat
Paleo or no paleo, the consumption of red meat believed by many to be unhealthy. This is based on studies that link high consumption of red meat to cardiovascular disease (CVD) and cancer, and it is usually explained as the increased level of saturated fat in the diet. This is not the whole story. The studies that claim this are flawed in their methods and/or reporting. They are usually population studies that take large groups of people and have them fill out food frequency questionaires (which are sketchy in their own right since they are based on memory and estimation). The results look at the frequency of cancer and CVD in the population tested. Those who ate more red meat had higher rates of cancer and CVD. What the study doesn’t mention, is that these people were also more likely to smoke, be overweight, obese, diabetic, inactive, or combinations of all of these characteristics.
In this cross over study (which is the most trustworthy type of study), two groups were divided among heavy red meat consumption versus fish and chicken consumption. The red meat group ate far more cholesterol and saturated fat, however, their HDL and cholesterol levels were the same as the fish and chicken group. Interestingly, in women only, red meat actually lowered blood triacylglycerol (=fat, TAG) levels and the fish and chicken increased the blood TAG levels. This is important because blood TAG levels are now thought to be more indicative of heart disease risk. Another interesting thing about this study was the carb intake, which usually regulates serum TAGs, was similar in both groups. This suggests that red meat has a TAG-lowering effect independent from simply replacing carbs from the diet with protein. Also worth noting is that the red meat group ate ~200 calories more than the chicken and fish group per day, but did not gain any weight. This is a great blog post that summarizes more studies on this topic.
Two other interesting studies were analyses of other studies. Looking at all the studies that met their standards and criteria, they determined factors that increase and decrease risk of heart disease.
- Increased risk factors: trans fats and high glycemic loads (AKA sugar, simple carbohydrates, and excessive carbs REGARDLESS of carb type).
- Decreased risk factors: fiber, fish, beta carotene, omega 3s, fruit, veg, nuts, monounsaturated fats, vitamins C and E, Meditteranean style eating, and whole grains. [I will get to grains a bit later.]
They noted the lack of evidence supporting the notion that reducing saturated fat intake will lower the risk of CVD. Furthermore, according to this study, there is no study yet that reduces saturated fat intake with no other changes to the diet. Meaning, if reductions in CVD were seen with reduced saturated fat intake, it could be due to the other changes made in the study, like reduced carb intake, increased omega 3 intake, etc. Also, note that polyunsaturated fats were not part of the decreased risk factor list, which is what we have increased in out diets by feeding our animals and ourselves lots of corn and vegetable oils.
Main point: Current research seems to indicate that it is not saturated fat that is responsible for our current state of heart disease, but rather the increased ratio of omega 6 to omega 3 fats in our diet. This doesn’t mean you can drown yourself in french fries and steaks. It means that grass-fed meats or extra lean conventional meats do have a healthy place in our diet, along with fish, healthy oils, nuts, and plants.
About grains and legumes
Grains and legumes (beans + peanuts) are out because they contain lectins and anti-nutrients. Wheat germ agglutinin (WGA) is one type of lectin, which is a molecule that can bind to other molecules in our body. Lectins are not broken down during digestion and can bind to receptors on the gut lining. This binding can lead to decreased digestion and absorption of other dietary proteins as well as transportation of the lectins through the gut and into the blood circulation. While they are transported, lectins can damage (in rough terms: “poke holes”) in our intestinal lining. These circulating lectins are then recognized by our immune systems as foreign invaders, and we will launch an immune response against them. Unfortunately, lectins can often resemble normal cells in our body, so these immune responses can essentially become immune attacks on our own tissues. Read: inflammation and auto-immune diseases. Because there is now perforations in the gut lining, other microscopic proteins from our diet can cross the lining, and immune responses can be raised against those proteins as well. Read: food allergies.
The strongest evidence against grains is definitely for those whom have autoimmune disease such as rheumatoid arthritis, celiac, lupus, Sjogrens, MS, T1 diabetes, and ulcerative colitis. This, this, this, and many more studies indicate that dietary gluten and grains do negatively impact those with decreased immune systems. However, not everyone has an overt immune disease. Like most things in this world, we are on a sliding scale. This study showed that those with celiac disease and people with increased genetic susceptibility to autoimmune disease had increased gut permeability when consuming a diet high in gluten. And as for completely healthy individuals with great immune systems? There is hardly any research. This study, ironically done by a student under the original Paleo-pusher, Dr. Cordaine, showed that healthy individuals did not see an increase in plasma levels of lectins after consuming 50 grams of gluten (although several explanations were offered for these results). However, this study did show that peanut lectins made their way through the intestinal lining and into circulation. This study showed the same with wheat germ agglutinin, but it was done on rats. This study showed that anti-bodies to WGA can be found in human circulation. Also, this research article is all about using lectins as a way to get pharmaceutical drugs absorbed more efficiently through the intestines, and cites studies that were done on human tissue. Therefore, it does appear likely that lectins are able to enter circulation and possibly cause damage.
Main point: Anyone with imperfect immune function (which you wouldn’t necessarily know if you were included in that group), and possibly everyone, can benefit from removing grains and legumes from their diet due to their lectin content. Even completely healthy individuals may benefit from lectin avoidance because lectins may at the very least be causing a constant low-grade inflammation in the body. Just try it for a few weeks and see how you feel.
The anti-nutrients in grains that I mentioned are protease inhibitors and phytates. Protease inhibitors are molecules that inhibit our enzymes from breaking down some of our dietary protein and lectins (which are proteins). I think that this is a bit exaggerated in The Paleo Solution because it is not as if your burger isnt going to get digested just because you ate it with a bun. That would require a LOT of protease inhibitors. Phytates are found in grains and seeds and can bind to important minerals, like magnesium, zinc, iron, calcium, and copper. Thus, when you eat phytates (which are mostly in the bran of the grains) they bind to those nutrients so that you cannot absorb them. While this is bad, I think it is also slightly exaggerated. Phytates will bind those nutrients, but not all of them! Then again, the typical American diet is grain heavy and lacking in fruits and veg, so I guess it could actually make quite a difference in a person’s nutritional status!
The case against dairy seems to be mostly based its effect of raising insulin levels. Insulin increases fat storage, and chronically elevated insulin levels can lead to insulin resistance. Clearly, for diabetics and people whom are overweight, this is bad. I also read that some studies correlate milk intake with auto-immune diseases. However, I am happy to report that some people actually can consume dairy given that they do not have any auto-immune issues, have a healthy gut and weight, and are not lactose intolerant. While strict paleo does say no dairy, even the some of the most hardcore paleo-pushers admit that grass fed, whole fat, organic dairy has its benefits. If it is grass fed and organic, it won’t contain any harmful pesticides or hormones, and will have a healthy fat profile. Additionally, if the dairy is raw, than the naturally occurring enzymes will help with the digestion and absorption processes. Proper dairy can be a great source of calories, protein, fat, calcium, and probiotics, however it can be difficult (or impossible) to get your hands on.
Main point: Try giving up dairy products for a couple weeks, see how you feel, and then re-introduce it. If you feel bloated and ill…. well now you know. If not, stick with grass fed, organic, whole milk dairy products. Those with auto-immune disorders or genetic susceptibility would also likely do well to avoid dairy.
When I first heard about how paleo excludes grains, even my beloved whole grains, I was disturbed. Almost mad! Here I was, with a blog all about eating healthfully and including whole grains into our diet, and this community was telling me that that was bad. I fought it. Whole grains have so many nutrients, like B vitamins and minerals! Whole grains have so much fiber! From my studies, I knew that the human body needs two kinds of fiber: soluble and insoluble.
Soluble fiber absorbs water, and thus slows digestion and makes us feel fuller, longer. It also helps feces transit.
Insoluble fiber is not digested by the body and adds bulk to the stool. This is important for maintaining bathroom regularity, which may be helpful with preventing colon cancer. Insoluble fiber is also a key source of food for gut flora (bacteria), which give us all sorts of immune and digestion benefits.
My first instinct was that without whole grains, I would only be getting soluble fiber from fruits and veggies. I feared that without my precious whole grain insoluble fiber sources, I would become a constipated, and thus grumpy, beezy. Turns out one can get both kinds of fiber very easily from a paleo diet.
- Soluble fiber is found in: fruits like apples, oranges, pears, and berries. Veggies like cucumbers, celery, and carrots. And nuts and seeds like flax, almonds, and psyllium.
- Insoluble fiber is found in: corn, seeds, nuts, zucchini, celery, broc, cabbage, root veggie skins, dark leafy veggies, onions, grapes, and other fruits.
While I have now made the agricultural revolution sound like the most terrible thing to ever have occurred, I must remind myself and others that it was this revolution that enabled us to feed more people and expand our population. In some ways, this is beautiful. More people, more innovation, peace, love, happiness. On the other hand, we have more people, but they are also fatter and sicker than ever before. So while the agriculture revolution certainly made food cheaper, it has also increased our medical care costs.
Another thing to think about is the environmental-friendliness of the paleo diet. Obviously, a lot of meat and animal products are consumed. While ideally the animals should be sustainably raised and grass fed, this sadly makes up only a tiny portion of our current agricultural system. Furthermore, it has been said that vegetarian diets are far more environmentally friendly than traditional diets. I have hardly done any reading on this, but it is something I have heard over and over again. I think the most important thing to keep in mind at the grocery store (or better yet, farmer’s market!) is that every dollar you spend on food is a vote. Hopefully with enough votes towards healthy, sustainable food items, they will become more affordable and we will slowly transition to a better agricultural system.