Monthly Archives: October 2012

What Exactly Is the Paleo Diet?

Pure paleo

Let’s be realistic: There’s no way to eat a Stone Age diet these days unless you live off the land, hunting, fishing, and gathering from what’s naturally available in the wild.  Few can do that, although it’s not impossible.  I’m going to specify my version of the paleo diet because I’m starting a paleo diet trial soon—a first for me.

How long has man had fire?  Biological anthropologist Richard Wrangham estimates hominins tamed fire and started cooking with it 1.8 million years ago.  So I’m cooking my paleo foods if I wish.

As with my beloved Mediterranean diet, definitions of the paleo diet vary.  The following guidelines are influenced by my review of blogs or websites by Loren Cordain, Julianne Taylor, Robb Wolf, and Kurt Harris.  The first three are closely affiliated with each other, so expect lots of overlap.  It’s simplest to define paleo by what’s not allowed.

What’s NOT Paleo?

Industrial vegetable oils (e.g., soybean, corn,safflower), legumes, dairy, refined sugars, grains, alcohol, and high salt consumption.

What Is Paleo? 

The focus is on minimally processed, in-season, locally available foods.  Many favor pastured, grass-fed beef, free-range chickens, “organic,” and the like.  I guess that’s fine if you can afford it; I choose to spend my money elsewhere.

Proteins

Meat, fish/seafood, eggs, poultry, and wild game.  Most paleo proponents favor lean meats over fatty ones; it’s debatable. Undoubtedly, our domesticated feedlot animals are fattier than wild game, generally.  Processed meats such as bacon would not be pure paleo, but many paleo advocates allow it.

Nuts and Seeds

Favor those with the best omega-6/omega-3 ratio (2 or 3:1), such as walnuts, almonds, macadamia, and cashews.  Modern humans eat way more omega-6 fatty acids compared to ancient hunter-gatherers.

Fruits and Vegetables

It’s probably best to favor those with lower glycemic index.  Examples are berries, melons, cauliflower, tomatoes, onions, and broccoli.  Most modern fruits and veggies  have been bred for large size and good looks.  Ancient fruits and veggies were smaller and had much more fiber per serving.

Tubers, Roots, Bulbs

These are OK per Cordain, and I agree.  Examples include potatoes, cassava, taro root, onions.  Some paleo proponents exclude potatoes.

Oils

Cordain favors oils such as canola, flax, olive. Others mention avocado oil.  Aim for a good omega-6/omega-3 ratio.  Lard is probably OK although obviously processed.

Herbs and Spices

Many of our favorites should be OK.  Wolf says balsamic vinegar is allowed, although processed, like all vinegars.  Vinegar is “natural,” as you might have noticed if you ever walked through an apple orchard with rotting fruit on the ground; you can smell the vinegar.

Condiments

Undecided.  Note that you can make mayonnaise from olive oil and egg yolk.

Miscellaneous

Olives?  They’re processed, but I’m inclined to keep them in the mix.  Coffee?  Not paleo, but I ain’t givin’ it up.  Consider limiting nuts to one ounce daily since most of them are high in omega-6 fatty acids.  Fresh foods are more purely paleo than canned or frozen, but I’ll not exclude canned and frozen.  Limit fruit?  Probably: in most environments, they’re available only seasonally.  Diet sodas?  Clearly not paleo, but I enjoy one now and then and don’t see any drawbacks to low consumption.

Steve Parker, M.D.

Update October 8, 2012

I learned today that my version of paleo, by coincidence, is similar to the Hartwigs’s Whole30 plan.  But they allow clarified butter or ghee, green beans, and snow peas.  I include potatoes, but Whole30 doesn’t.

Are We Fat Because We’re Less Active?

Less active

Much of the world has seen a significant decline in populaton-wide physical activity over the last few decades, according to Nike-sponsored research reported in Obesity Reviews.

Countries involved with the study are the U.S., U.K., Brazil, China, and India.  How did they measure activity levels?

Using detailed historical data on time allocation, occupational distributions, energy expenditures data by activity, and time-varying measures of metabolic equivalents of task (MET) for activities when available, we measure historical and current MET by four major PA domains (occupation, home production, travel and active leisure) and sedentary time among adults (>18 years).

The authors note the work of Church, et al, who found decreased work-related activity in the U.S. over the last half of the 20th century.

Inexplicably, they don’t mention the work of Westerterp and colleagues who found no decrease in energy expenditure in North American and European populations since the 1980s.

More active

My gut feeling is that advanced populations around the globe probably are burning fewer calories by physical activity over the last 50 years, if not longer, thanks to technologic advances.  We in the U.S. are also eating more calories lately.  Since the 1970s, average daily consumption by women is up by 150 calories, and up 300 by men.  I’m surprised we’re not fatter than we are.

Steve Parker, M.D.