Diet Change: Vegan to Grain-Free

I am an extremist. The simplicity of extremes is appealing as one avoids the complexities of grays. For the past two years or so, I have followed a rather strict vegan diet motivated by the health benefits claimed by The China Study, and not particularly by the idea that it is immoral to eat animals. Recently I have had a number of questions in my mind as to the evidence for and against such diets, and ultimately decided to add preferably lean, organic and non-feedlot meats back into my diet. At the same time, I am experimenting with removing grains from my diet. Here’s why:

Is the evidence for a vegan diet very strong?

The China Study presents a few lines of evidence to support that protein, probably by IGF-1, can increase cancer risks. However, upon reading The Protein Debate, it seems to me that Dr. Campbell believes all protein does this and a primary reason to go Vegan is that such a diet very likely limits total protein to less than 10%. If you are vegan and you eat enough legumes or vegan protein supplements to get that number to 20-30%, are you not violating the fundamental argument for the anti-cancer benefit?

Virtually none of the people studied in The China Study were vegan. An extrapolation is made that goes from low animal protein to zero should be helpful. Is that reasonable? As recently as 1998, new nutrients were recognized as essential. What essential nutrients have yet to be discovered? Perhaps even low levels of meat supplies something essential that is as of yet unknown, without which health is impaired. No population of humans that I am aware of have lived on vegan diets for their entire lives. I’d prefer to be conservative and adopt a diet with some consensus behind it, namely, what did groups of healthy and long-lived people eat? The Blue Zones project seeks to address this. They identified many groups of long-lived people. Only one of them had significant populations of vegetarians (Seventh-day Adventists), and even most of them consumed some fish and eggs. Granted, Adventists who ate more meat had higher cancer rates, but how controlled were the studies? Were those processed meats? A recent meta-analysis found processed meats increased heart disease and diabetes, but not red meat. Many studies lump all meats together, which may be throwing the baby out with the bathwater.

What will I eat?

If you are not on a tight budget, you have many options for food. My current experiment is to add meats back to my diet, but remove grains. Why am I removing grains? I was influenced by two arguments. The first being The Paleo Diet, the second being general low-carb diets that avoid grains such as rice, bread, pasta, and so on to reduce insulin production. The core idea is that there are some foods to which were are more adapted to eating than others, and grains are particularly bad. This is a reasonable hypothesis, but it needs to be substantiated by evidence before it should be treated as true. My ancestors have likely been farming for 10,000 years or more, and that may have been enough time to completely adapt to a grain-based diet. However, for this experiment, I’m removing grains. From a standpoint of nutrient density, grains are not so great. Take a look at the The World’s Healthiest Foods. Very few grains compare favorably against fruits, vegetables, and meats for nutrients per calorie. I am going to focus on very low glycemic index foods. The exception will be during or after longer running events or workouts. I will use bananas, watermelon, pineapple and sweet potatoes after workouts to get non-grain high-GI foods. I will also eat lentils and beans, which are low-GI, but not Paleo-approved. Some might say, this sounds like an Atkins diet, and that is not healthy. It appears to me concerns about lower carbohydrate diets seem to lack evidence. A recent 2-year study, sometimes called the ATOZ study, found Atkins dieters lost more weight and improved metabolic risk factors more than traditional, Ornish or Zone dieters. I can’t find any evidence that these diets are a risk. Can you?

Should you change your diet?

I believe humans are very metabolically flexible. If you have no problems with your health, athletic performance, or happiness that could plausibly be connected to diet, and you are pleased with your diet, I’m not sure there is strong evidence to change. If you are overweight, struggle to maintain your weight, are frequently injured, or feel that your workouts don’t go well, perhaps changing your diet is worth a try. I don’t think anyone can convincingly say much about diet other than if you are obese, it is harming your health. If your diet is not preventing obesity, you probably need a change.

Update 2/27/2011: I found this criticism of the China Study to make good points (and a few of the same ones I made). It would be interesting to see more a response to these questions and criticisms from Dr. Campbell.


The Cost of Eating Well

About a month ago, I was shocked by an interview I heard while driving home. The radio program Florida on the Line had Holly Benson, secretary of the Agency for Health Care Administration, as a guest. The interviewer asked Holly if the economic downturn would have an impact on health. Holly responded, “just because you’re poor doesn’t mean you’re unhealthy; it just means you have a lot more time to go running.”

I was disappointed that this question was not seriously addressed (and by the callousness of the response). In fact, being poor does impact your health. Those with the lowest income have the highest rate of obesity. The fact is, the cheapest foods are not the healthiest (related article at CNN). Sugar is cheap:

All that corner-store processed food is relatively inexpensive – artificially so. Researchers say that many junk foods contain high-fructose corn syrup, made from government-subsidized corn crops. Federal help keeps the cost of syrup-containing foods such as sodas, fries and even burgers down. Drewnowski said that healthful, unsubsidized foods like spinach cost five times more per calorie to produce, thus driving up the price (from Philadelphia Inquirer).

As an engineer, I like numbers. So, what are some example calories-per-dollar ratios? Since I try to eat healthy and keep a spreadsheet of all the foods I eat at home, computing calories-per-dollar for all my recipes is easy. Here are some examples from my spreadsheet:

Food calories/dollar
Peanut Butter 978
Peanuts 889
Oats 741
Whole Wheat Bread 420
Almonds 387
Kashi Bars 316
Nonfat Milk 268
Canned Beans 262
Pistachios 258
Grapes 185
Frozen Strawberries 159
Fat-free Yogurt 122
Tempeh 115
Canned Tuna 107
Oranges 107
Cooked Turkey 89
Carrots 62
Blueberries 54
Tomato 48
Spinach 28

Notice anything? All the produce is significantly more expensive than the fats and grains. McDonald’s sells cheeseburgers for 59 cents on some days. Since those cheeseburgers are about 300 calories, that gives you 504 calories/dollar. Of all the things in the above list, McDonald’s cheeseburgers are the fourth cheapest! If you eat 2000 calories/day, you could survive on 4 dollars a day on McDonald’s cheeseburgers. You’d get more than 100% of your fat and cholesterol, and only 8% of your Vitamin C, but you’d get 100% of your calories.

Perhaps you like sweets instead of cheeseburgers. You can buy 56 oz of Peanut M & M’s for 15.99 which gives you 8065 calories, or 504 calories per dollar, the same as the cheeseburger!

Being healthy and avoiding disease requires more than cheap calories, it requires getting sufficient vitamins and other nutrients. Unfortunately, in the United States, between 5-17% of the population is Vitamin C deficient.

If you were at risk of starving would you purchase spinach at 28 calories per dollar or peanut butter at 978 calories per dollar? This is a problem I don’t hear addressed very often in the obesity discussion. We need to look more at the cost-per-calorie of healthy choices. This is an area where the government could help. We should tax unhealthy choices, and subsidize healthy choices. Since humans’ tastes are set for a food landscape that does not exist today, namely scarcity of sweets and fats, we need to leverage other mechanisms such as economics to help make better choices.

The Freakonomics of Human Fuel Economy

With gas prices high, I’ve heard a lot of articles assert that biking gives infinite miles per gallon. While it is true that humans don’t use gas, it’s not true that they don’t use energy.

When one walks, runs or bikes, one burns energy that would otherwise go unburned. For walking (4 mph), running (10 mph), and biking (11.9 mph) a 155 lb person burns 281, 1126, and 422 calories per hour respectively (according to this site). We can compute the calories per dollar of cheap food sources, such as grains (741 calories/dollar) or peanuts (867 calories/dollar). Let’s assume one can average 800 calories per dollar (which assumes spending about $2.50 per day on food on a 2000 calorie diet), which is a pretty generous assumption.

Let’s compute the miles/dollar assuming 800 calories/dollar: walking gives 11.4 miles/dollar, running gives 7.1 miles/dollar, and biking gives 22.6 miles/dollar. Assuming a gallon of gas is worth 4 dollars, we can express miles per dollar as miles per gallon. This means walking, running and biking converts to 45 mpg, 28 mpg and 90 mpg respectively. Very few Americans spend as little as $2.50/day on food. In fact, $10/day is probably more realistic. Assuming instead 200 calories/dollar (10 dollars/day), we get something like 11 mpg, 7 mpg, 22 mpg for walk, run, and bike. The only way I can beat the economy of my Prius is to bike and fuel that bike ride with ultra-cheap food sources.

Don’t get me wrong, exercise is great. I run, walk and bike a lot. Additionally, most Americans are eating more calories per day than they need, and could possibly bike for transportation without increasing their calorie intake. But, it is not the case that humans are much more efficient than cars.

Menus Without Labels

Once upon a time, when a gentleman would take a lady to a restaurant, the lady would get a menu without prices. The idea is clear, the lady should enjoy her meal without worrying about the price. Today, almost all menus are printed without labeling the calories of the meal. The Center for Science in the Public Interest has a campaign to change this.

There are 3500 calories in a pound, and 365 days in a year. Eating an extra 9.6 calories a day, puts a pound on you every year, which is the average amount of weight gain in a recent study. So, if your diet calls for about 2000 calories, you have to be accurate to about 0.5% in your caloric estimates to only gain about 1 pound a year. Unfortunately, people underestimate the calories of meals, and are particular bad at estimating the calories of big meals. Further, only 11% of consumers could identify which choices had the most calories at McDonalds or Denny’s and 9 out of 10 underestimate the number of calories of less-healthy choices by an average of more than 600 calories. You can try your hand at it: take the online quiz! (I got 2/5 correct).

Let’s look at this thing from the other direction. Why not pass a lady’s menu to everyone? You guess the calories and the cost. Clearly steak is more expensive than chicken! They don’t need to tell you that do they? To make it even easier for the restaurant, they don’t even tell you the price at the end. You just give them your credit card/checking account number and they take the money. At the end of the year, you get a report on how much you owe for food. This might help with obesity. At the end of a few years, when you overeat, you’re not only obese, you’re bankrupt. Maybe that will improve the consumer’s powers of estimation.

I don’t think the obesity problem is a lost cause. I do think the secret is pretty simple:don’t eat too many calories. Here are some simple tips: don’t drink sugar sodas. Don’t eat mega-calorie desserts like Dairy Queen Blizzards (1000), Cheesecake Factory Cheesecakes (1050), or Chick-fil-a milkshakes (790). Never ever ever eat an Awesome Blossom (2710 calories!). If you want dessert, try a cup of strawberries (77 calories) or other fruits. Fruit has carbs (gasp!) but it also has a lot of fiber and water and is very filling. On the other hand, chocolate is not very filling and it’s pretty easy to eat 1000 calories of it. If you are out to eat and must order dessert, try the mini-desserts some restaurants offer. These weigh in at 200-300 calories. WebMD has some tips on cutting calories.

I hope my state of Florida follows San Francisco and New York City to require menu calorie labeling. Here are some examples of menu labels including pictures from NYC Starbucks.