The real reason why the food pyramid isn't working...

In 1992, the U.S. Department of Agriculture officially released the food pyramid. The food pyramid was supposed to help us make dietary choices that would maintain good health and reduce the risk of disease.

Unfortunately, there's little evidence to suggest that the food pyramid has convinced most people to change the way they eat. In fact, despite one of the main messages of the food pyramid that all fat is "bad", surveys show that the amount of fat in the average diet has actually risen!

Food pyramid

The shape of the food pyramid shows the proportions that various food groups should contribute to the total diet. Food groups at the wide base of the pyramid, such as bread, cereal, rice and pasta, are supposed to be eaten in greater amounts than foods near the top. Fats, oils and sweets are at the top of the food pyramid, and are supposed to be consumed sparingly.

Many studies, however, show that not all fats are bad, and not all carbohydrates are good. Even when the food pyramid was being developed, nutritionists knew that some types of fat are essential to health. Putting them all in one category ignores the fact that different fatty acids have very different effects on your health.

Fish oils, for example, which contain omega-3 fatty acids, have many proven health benefits. On the other hand, trans-fatty acids — found in varying amounts in foods such as crackers, cookies and some margarines — are linked to an increase in the risk of heart disease.

There are actually far more fatty acids than many people realize. Even minor differences between them are often very important. Individual fatty acids are sometimes referred to by their chemical names.

The omega-3 fatty acid found in flaxseed oil, for example, is called alpha-linolenic acid. You'll see this written as C18:3n-3. Although it might look a little complicated at first, these letters and numbers give you plenty of information about the properties of the fat.

• A fatty acid contains a chain of carbon atoms bonded together. C18 means there are 18 carbons in the chain.

• The next number (in this case, 3) tells you that there are three double bonds in the chain.

• The final piece of information — n-3 — tells you where the first double bond is located.

Compare this to eicosapentaenoic acid (known as EPA), one of the omega-3 fatty acids found in fish, and you'll see there are a few small (but important) differences.

Eicosapentaenoic acid is also written as C20:5n-3, which means that it has 20 carbon atoms in the chain — two more than alpha linolenic acid. That's why you'll see alpha-linolenic acid called a short-chain omega-3 fatty acid, while EPA is known as a long-chain omega-3 fatty acid.

So, where did the original food pyramid go so wrong?

In part, the people behind it fell victim to a desire to simplify their dietary recommendations, deciding it would be too difficult to educate the public about these subtleties. Instead, they put out a clear, simple message that all fat is "bad" — which, of course, it isn't.

At first glance, it might appear that the food pyramid has convinced everyone to eat less fat. In 1988, for every 100 calories in the average male diet, 37 of those calories came from fat. By 1995, this figure had dropped to 33 calories. The trend was similar for women, where the percentage of fat calories dropped by roughly the same amount.

However, while the percentage of fat in the diet has dropped, the absolute amount has actually gone up.

• Back in 1988, men were eating an average of 95 grams of fat each day. By 1995, this figure had risen to 101 grams.

• The average daily fat intake for women has also risen, from 63 grams in 1988 to 66 grams in 1995.

The reason for these apparently conflicting results is that most people are simply eating more food! Between 1988 and 1995, daily calorie intake for men rose from 2,272 to 2,667 calories. That's an increase of 395 calories — roughly the same number of calories you'll find in a Snickers® bar. Women are also eating more, with energy intake rising from 1,543 to 1,758 calories daily.

The bottom line is that the food pyramid appears to have had little or no impact on the eating habits of the average American. Given the fact that the food pyramid says all fats are "bad" and all complex carbohydrates are "good", it's no wonder people aren't paying a lot of attention.

Reference
Kennedy, E.T., Bowman, S.A., & Powell, R. (1999). Dietary-fat intake in the US population. Journal of the American College of Nutrition, 18, 207-212