Recently, there was a pretty funny hashtag trending on Twitter: #FiveWordsToRuinaDate. The world-wide tweets ranged from serious (religion, politics) to silly (diets, clothing brands) to dirty (use your imagination). Since my Twitter network happens to include a lot of dietitians, it was only a matter of time until the hashtag was repurposed and #FiveWordstoRuinaDateWithaDietitian blew up my Twitter feed. Here are some good ones:
“Juicing has changed my life!” – @LoritheRD
“I don’t eat food with chemicals.” – @nutrevolve
“Dr Oz recommended this detox.” – @EverydayRD
“I don’t eat white foods.” – @RDAmber
“I’ve got this gastrointestinal problem…” -@FoodieRD
And my own:
“Humans didn’t evolve to eat…”
Insert any number of foodstuffs (grains, cow’s milk, beans, etc). Yes, this is a nod to Paleo.
The modern Paleo movement is pretty famous for its philosophy that today’s humans are so sick because we are eating a diet we have not “evolved” to eat. Our hunter-gatherer ancestors that roamed the planet 10,000 years ago did not eat grains, sugar in excess, legumes, and cow’s milk, so we shouldn’t be either. Foods allowed on the diet are: grass-fed meat and poultry, fish, most vegetables, most fruits, most seeds and nuts (except peanuts). Foods not allowed are: grains, dairy, sugar, legumes (beans, peanuts, green peas).
Anyone with a basic understanding of evolution (which is about ALL I have – head over to my buddy Kevin Klatt’s blog Nutrevolve for well-written science-based posts about nutrition, genomics, and evolution) knows that it’s a continuous process without a master plan or culminating end point. There was/is/will be no single point in time that we humans were eating the perfect diet. Nor was there just ONE Paleolithic diet. The food that Paleo people ate varied depending on the region and season.* Throughout human history, as new potential food sources became available, humans evolved physiologically to be able to consume them IF consuming them conveyed some sort of benefit to survival. This is called natural selection. Lactase persistence (the sustained ability to digest lactose after weaning from breast milk) is more recent example. You may know that about 65% of humans today are lactose intolerant because of the decreased production of the lactase enzyme after weaning. But 10,000 years ago, that number was close to 100%. Lactase persistence was selected for among populations that began domesticating cattle and drinking their milk, which conferred nutritional benefits. These people were surviving longer than the lactose intolerant people in their populations, and were more fit to reproduce and pass on their lactase persistence to their kids. The fact that this selection for lactase persistence has occurred fairly recently (in the last 10,000 years)1, certainly suggests human evolution is a continuous, ongoing process.
Accepting evolution and natural selection as scientific fact is mutually exclusive from believing in an ideology that suggests there was a single point in time that humans were perfectly evolved to their surroundings. You can’t have it both ways.
This is where my rant ends. Let’s get back to the Paleo diet. From now on, when I say “Paleo”, I am referring to the modern fad diet, since we can’t possibly replicate the diet of actual Paleolithic peoples in our industrial agricultural society. One, we don’t really have a complete picture of what they ate and in what proportions. But further, foods like meats, fruits, and vegetables that would have been hunted, gathered and eaten 10,000 years ago are far cries from today’s farmed, domesticated, and carefully bred versions.
(Wild broccoli and wild avocado. This is likely what actual Paleolithic people were working with)
I do think the Paleoers have one thing right: the Standard American Diet (SAD) is really crappy. And the available evidence points to the SAD as having a lot to do with why we are so sick with lifestyle-related chronic illnesses. Cardiovascular diseases like hypertension, coronary artery disease, and heart failure are the leading cause of death in the United States2. A major risk factor for CVD is dyslipidemia (an unfavorable balance of lipids found circulating in the blood – total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides).
Type 2 diabetes is on the rise in the US, with almost 10% of the population carrying the diagnosis. Obesity is the major risk factor for type 2 diabetes3, and obesity is directly linked to the SAD. Overconsumption of refined grains and simple sugars, and calories in general, desensitizes our cells to insulin (whose job it is to clear sugar from the blood).
We have evidence that switching from the SAD to a diet rich in fruits, vegetables, and whole grains, with a decrease in saturated fats and refined grains in favor of mono- and polyunsaturated fats, will confer health benefits and reduce the risk of cardiovascular disease and diabetes4,5,6,7,8. What we DON’T have, however, is evidence that the Paleo diet is helpful in this way.
Paleo supporters will beg to differ, and they’ll point to a few studies 9,10,11,12,13 to make their case.
Unfortunately, these studies are pretty worthless. Most are really short term (one is 7 days!), have small sample sizes, and don’t have a control group. The version of the Paleo diet used differs across the studies, adherence to intervention and control diets vary, and the murky methods sections of some of them leave much to be desired. Further, since the Paleo diet is inherently lower in calories than the SAD, and potentially the Mediterranean diet, the Paleo groups in almost all studies lost more weight. We know that weight loss itself causes favorable physiological changes in metabolic parameters like blood lipids and glucose levels. In these studies, we cannot say for sure that it was the Paleo diet or kcal restriction and subsequent weight loss that improved those measurements.
When someone goes from the SAD to Paleo, they will probably lose weight and feel better. They may see improvements in their blood lipid levels. They may see improvements in measurements of glucose tolerance like blood glucose levels and hemoglobin A1c. Let’s take a closer look and see what’s going on here:
Typical SAD Day (should be stated, this is based on  my experience as an RD in nutrition counseling and diet recall, and  living in America for 31 years):
Breakfast: sugar sweetened cold cereal w/ milk OR packaged instant oatmeal OR fast food breakfast like egg/sausage/cheese on a bagel
Snacks: cookies, cakes, chips, pretzels, candy (including ‘low fat’ versions of these items)
Lunch: processed lunchmeat, white bread, mayo, mustard OR fast food/take out (Mexican, Asian, pizza) OR processed frozen meals like Lean Cuisine
Snacks: more cookies, cakes, chips, pretzels, candy
Dinner: Possibly the only healthy-ish meal, if cooked from scratch and balanced (half the meal veggies/fruits, ¼ lean protein, ¼ whole grain starch). If not, frozen meals, boxed/prepared meals, take out, and ice cream for dessert
Beverages: soda, sugar sweetened teas and juices, lemonade, milk, coffee and coffee drinks
Typical Paleo Day:
Breakfast: fresh eggs, salad w/ oil vinegarette, some kind of fresh, unprocessed meat
Snacks: nuts, seeds, raw veggies, raw fruits
Lunch: lean, fresh (uncured, unprocessed) meat (chicken, fish, beef) more vegetables
Dinner: same as lunch, basically
Beverages: water (some Paleoers drink tea and coffee)
It should be pretty obvious that switching from a SAD diet high in processed foods with high sugar, sodium, and fat content to the Paleo style of eating, which includes only whole, minimally processed foods cooked or prepared from scratch, would lead to improved health. Refined carbohydrates are gone, so we’ll see improvements in glucose tolerance and blood lipids. Calorie intake will decrease (veggies are super low cal, but all that fiber will fill you up) and the weight will come off.
The modern Paleo fad diet, followed strictly, is a healthier way of eating when compared to the SAD, especially if the meat is lean and the fats are mostly unsaturated. I don’t think any dietitian would argue with me on this one. The problem occurs when Paleo gets twisted. To deal with the monotony of the allowed Paleo foods (remember, our ancestors didn’t CHOOSE this – it was all that was available; it was Paleo or death), well-intentioned Paleoers are coming up with TONS of recipes and ideas for snacks. There are paleo bars, paleo cakes, and some paleo followers eat gluten-free versions of breads (despite not having Celiac Disease or gluten sensitivity – the only medical reasons to cut out gluten). Some put 2 tablespoons of butter in their coffee and call it breakfast (AKA Bulletproof Coffee). This is where the excess calories start to creep back in. See, to keep a pretty restrictive diet sustainable, people will naturally, over time, look for loopholes and cheats. Paleo doesn’t allow me a Cliff or Luna bar, but I can have a NoGii bar. I can have Paleo People grain-free granola. I can make copycat Hostess Chocolate-Frosted Donuts Paleo (these actually look pretty darn good).
If people stopped saying Paleo is how we were “intended” to eat, I would hold a bit less contempt in my heart for the Paleo soap-boxers. I actually do agree with specific aspects of the modern Paleo fad diet, especially the focus on whole, minimally processed foods, vegetables and fruits, and lean meats. It’s a bit more restrictive than the Mediterranean diet, which is why I won’t recommend it to someone starting from square one and currently eating the SAD. Its life-long sustainability is questionable. Adding in moderate amounts of whole grains, legumes (lentils, beans, peanut butter) and dairy (yogurt – hello!) allows more variety, more ability to create a new, healthy lifestyle we won’t get bored by in a few months.
All that being said, if you are thinking of doing Paleo (or already follow it), keep a few things in mind.
First and foremost, if you have any cardiovascular disease or risk factors for it (family history, smoker, high cholesterol), please consult your doctor or a registered dietitian before going Paleo (or starting any restrictive diet).
If you’re basically healthy and looking to lose weight or kick the SAD out the door, think about these points. The Paleo diet, if followed strictly, is low in calcium, manganese, vitamin E, vitamin D, and iodine. Make sure you’re including dark greens like kale and broccoli for calcium, nuts and seed for manganese (typically found in grains) and vitamin E, and maybe add a little iodized salt (sea salt has no iodine). If you get 10 minutes of direct sun exposure a day, you are probably getting adequate vitamin D. It’s also found in high amounts in salmon and swordfish. If you’re not eating 2 or 3 servings of these fish a week, though, you may need to take a supplement (ask your doctor to check your Vitamin D level – no need to supplement if you’re not deficient). If you are very physically active, make sure you include starchy vegetables like winter squash, beets, yams, and potatoes (technically not allowed on true Paleo). Don’t get hung up on grass-fed meat – it’s only slightly higher in omega-3s than conventional meat and if you’re eating fish and ground flax seed, you’re good. And just because meat is encouraged doesn’t mean it has to be the star of your meal. In fact, actual meat consumption of the Paleolithic people would have varied immensely by region and time of year and there’s no evidence available to suggest their diets were made up primarily of meat. Make half your meals vegetables.
Finally, think critically about the information you’re getting from online blogs and forums, especially if the folks posting on them have no background or training in nutrition, science, or medicine. Currently we lack good-quality research to support long term health benefits of the modern Paleo fad diet. Paleo supporters will throw around research articles as credible “proof” that Paleo is superior, but those studies have some serious limitations.
*For a more detailed look at what Paleolithic people really ate, and how radically different specific foods were compared to their modern counterparts, check out this TEDx talk: http://www.youtube.com/watch?v=BMOjVYgYaG8.
1. http://www.ucl.ac.uk/mace-lab/gallery/lactase (lactase persistence)
4. Estruch, R, et al. (2013). Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med. 2013 Apr 4; 368(14):1279-90.
5. Mente, A, et al. (2009). A systematic reviewe of the evidence supporting a causal link between dietary factors and coronary heart disease. Arch Intern Med. 169(7):659-69.
6. deLorgeril, et al. (1999). Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction: final report of the Lyon Diet Heart Study. Circulation. 99:779 – 85.
7. Schwingshakl, L, et al. (2014). Adherence to a Mediterranean diet and risk of diabetes: a systematic review and meta-analysis. Public Health Nutr. 22:1-8.
8. Koloverou, E., et al. (2014). The effect of Mediterranean diet on the development of type 2 diabetes mellitus: a meta-analysis of 10 prospective studies and 136,846 participants. Metabolism. 63(7):903-11.
9. Lindeberg S, et al. (2007). A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease. Diabetologia. 50(9):1795-807
10. Osterdahl M, et al. (2008). Effects of a short-term intervention with a paleolithic diet in healthy volunteers. Eur J Clil Nutr. 62(5):682-5
11. Jonsson T, et al. (2009). Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Cardiovasc Diabetol. 8:35
12. Frassetto, et al. (2009). Metabolic and physiologic improvements from consuming a Paleolithic, hunter-gatherer type diet. Eur J Clil Nutr. 63(8):947-55
13. Ryberg, et al. (2013). A Palaeolithic-type diet causes strong tissue-specific effects on ectopic fat deposition in obese postmenopausal women. J Intern Medicine. 274(1):67-76