Correlation verus Causation

Mistaking correlation for causation.

This is probably one of the biggest mistakes we make in nutrition and weight loss research.

If you added up every single grammar error and spelling mistake I have made on this blog over the past year, it still wouldn't even come close to the amount of times people have mistaken correlation for causation in weight loss research.

There are a lot of fancy definitions for correlation, but I like to think of it this way - If two 'things' are correlated, this means they are related.

This is very different than Causation.

Causation is when you change one thing, and you cause another thing to change.

They are similar, but quite different.

For example, I live in the small (but rapidly growing) town of Waterdown. If I were to conduct a research study on the women in Waterdown between the ages of 16 and 22, looking at the relationship between their body composition and the clothing that they own, I would most likely find a significant correlation that would read something like this:

There is a significant correlation in women who own Lululemon workout pants and Nike running shoes and having a low body fat and lower body weight. That is, the women who owned more pairs of workout pants and Nike running shoes, would tend to be leaner and lighter then women who owned less.

This is a correlation.

Obviously the Lululemon pants and Nike shoes did not CAUSE these women to be lighter and leaner (even though it would be great for sales), rather the women that own these clothes tend to go to the gym more often and live a 'fitness lifestyle' that includes watching what they eat, thinking about their health and working out regularly.

So the correlation is in the lifestyle.

This finding happens a lot in research and is often mistaken for causation.

Take for instance all the research that shows that people who eat more frequently tend to be leaner and weigh less than people who eat less frequently.

This would be a great example of a lifestyle correlation.

Over the last ten or so years the trend in the health and fitness industry has been to promote the idea of eating more frequently. And, as a result, people who are heavily into fitness and health tend to eat more frequently then people who are not into the health and fitness lifestyle.

This creates a lifestyle correlation. This does not mean that eating more frequently CAUSES a person to be lean...it just means that people who are lean live a lifestyle that (currently) includes multiple meals per day, because this is what is popular.

But what happens when we remove the lifestyle variable?

Well that is exactly what Karine Duval and her team examined in the research publication "Physical activity is a confounding factor of the relation between eating frequency and body composition"

When you removed physical activity from the equation, the correlation between meal frequency and body composition disappeared.

Or, as they put it:

"It is interesting that the associations between eating frequency and adiposity disappeared after correction for physical activity energy expenditure and VO2peak"

A perfect example of well conducted research proving that we often mistake a correlation for causation.

Scientific research is very difficult. And trying to control all of the components of a persons life so that you can make definitive statements about cause and effect still eludes even the most skilled researcher.

BP

The Cause of Obesity in North America

I think it's time to let you in on a little secret.

I don't think fat causes obesity. I also don't think it sugar either. The same goes for high fructose corn syrup and soda pop.

In fact, when it comes to the being overweight I think all of these things are only the tools that make us heavy, they are not the cause.

In my opinion, the single leading cause of obesity is this - We have all been taught to not be discriminating when it comes to what we eat.

Think about it. If I offered you a watch for 2 bucks that was made by "Rolecks" would you buy it from me? Would you wear it and show it to all your friends? How about if I offered you a 10 dollar "Goochi" purse? You'd probably laugh at me and walk away, right?

We may turn our noses up at cheap imitation clothes and accessories, but we have no problems accepting cheap imitation food.

Seriously, a 99 cent burger? An 8.99 Lunch special steak that is tough and tasteless? Where did we learn this complete lack of eating class?

We have taste buds for a reason. Their purpose is to allow us to discriminate between good food and bad food. Fresh or Spoiled. Ripe or Rotten. Yet over the last 100 years, the food industry has figured out how to trick us into thinking bad things taste good.

The right pictures, the right colors, the right wrapper and the right massive levels of sweet and salt. That's all it takes to completely blind our taste buds.

If you have ever had a chocolate flavored protein shake ask yourself 'did it actually taste like a "rich and creamy" chocolate shake?'

I sampled a protein shake last night.

I went to the store and picked out the one brand that said it was the 5 time award winner for best tasting product.

I took it home, mixed it exactly as instructed. At first taste, it was fine. But when I really truly tasted it do you know what I tasted?

I tasted sweet. Sweet combined with aluminum, tin, and the unmistakable zing of artificial sweeteners.

It did not taste good at all.

My coffee this morning tasted exactly like it always does. When I stopped and actually TASTED my coffee I realized it was horrible. I can't even describe what it tasted like, but it wasn't coffee and it wasn't good. I drank it anyways. Why?

As I am writing this I am eating a "Caramelt" chocolate bar (In the name of research of course!). It doesn't taste like caramel, chocolate, or for that matter fresh.

It tastes sweet, waxy and preserved.

I have eaten good chocolate before, the kind that is rich and melts in your mouth. This was NOT good chocolate. It was artificial. It was imitation chocolate.

We eat this horrible imitation food on a daily basis. Worse, we eat way more of it than we want to.

This is why I beleive that our loss of ability to discriminate between good foods and bad foods is the root cause of obesity.

Forget inactivity, sugar or saturated fat. It is the simple fact that the food industry has figured out how to fool our taste buds into thinking that every piece of food that is made available to us
tastes good and is desirable - THIS is what is causing all of us to become heavier than we want to be.

But it's not just our taste buds that have been fooled.

Our brains have been tricked too. We now eat for 'nutrition'. We eat because we just finished our workout. We eat to get some protein, or vitamin C, or any other new and popular nutrient that just might save our life. And worse of all, we eat because some health expert told us if we don't eat, we'll get fat.

So we are actually guilt-tripped into eating bad tasting food. So we accept imitation food, because we are led to beleive that eating something is better than eating nothing.

The alternative, is to be a discriminating eater. Be a connoisseur of food. Be picky and only eat good tasting food. If good food isn't available, you don't have to eat (if you've read Eat Stop Eat, you know that we can easily go 24 hours without eating, with nothing but good consequences).

Pay good money for good food, but eat less often. Stop and think about just how fun that could be. By eating less, and eating less often, you can allow yourself to eat good foods. And not just dessert, but everything. Every single piece of food you put in your mouth could actually be full of rich flavor.

A well made creme brule will always, always taste better than any fast food treat. Real ice cream will always taste better than imitation frozen milk ingredients. A good steak is better than a cheap one. Fresh strawberries are better than frozen.

Sure it is more expensive, but you pay for quality. And, if you are eating less, you really won't be paying more for food in the long run.

Don't worry about the fat content or sugar content or how much phytochemicals are in the foods you eat. By being picky you will eat less, and eating less is far more important to your health then the percentage of a nutrient in your foods.

Plus, by eating better tasting foods, you will almost always be eating healthier foods.

By increasing your expectations of your food, and aiming for quality and flavor, overeating will never be an issue.

Most importantly, don't be afraid to eat less and eat less often, especially if the trade off is truly enjoying the foods you eat.

BP

Brad's Predictions for 2008

Alright, I know I'm a little late on this one, but here it goes...these are my predictions for the health and fitness industry in 2008.

1)Eat Stop Eat will be the next Atkins Diet

This prediction may sound a little conceited, but the idea of using short periods of fasting for weight loss is definitely catching on. And it shares a number of similarities with the Atkins Diet - it is incredibly effective and it is controversial because it flies in the face of some of our current nutrition fads, just as the Atkins Diet did. The only difference is, Eat Stop Eat is flexible and easy, so for this reason it may become quite as popular as Atkins (for some reason, people love complexity).

(The next big thing?)

2)People you trust are going to start pushing supplements on you

eTrainers and other on-line fitness experts who used to "rage against the supplement industry" will soon start pushing you on supplements as they begin to realize what the supplement industry has known for a longtime - the reoccurring income these products can generate is a quick and easy way to make a lot of money.

(These guys are Different...this stuff is great)

3) We will start to realize that our obsessive compulsive relationship with food is slowly ruining our lives.

Eat six times a day. Only eat protein with fat. Eat low glycemic. Eat to "fuel the machine". I think this year people will finally start to realize that the obsession with trying to figure out what and how to eat to lose weight has left us as a group of neurotic eaters who are more confused and frightened of food than we ever were before.

(I don't care how much it weighs, I'm eating the whole apple!)

4) Everyone will be taking pictures of their food and blogging it.

I think it may have been either Art Devany or Dr. Eades who started this trend, and they both did it with good intentions. It started off as a way of showing people that eating lower carb foods can still involve very appealing looking foods. In 2008 this idea will be bastardized and turned into a competition of "look how healthy I eat" between health and fitness bloggers.

(I'd post a pic of what I ate today, but I was fasting)

BP