definitions

Nutrition labels aren’t entirely useless—their regulations are surprisingly thorough and they provide basic information about most of the food we eat. Unfortunately, they also legally allow misrepresentation (mostly of serving portions), which the FDA and other regulatory bodies are often unable to validate. The far larger issue is understanding what those numbers and ingredients mean.

Over the course of several weeks, I will build a general nutritional knowledge base. Some bits will be scientific, while others will be more holistic. I will provide specific ways to improve your diet while still eating things you like. I’ll also explain why those methods work.

Here’s some information to build our foundation:

What we consider calories are actually kilocalories, or 1000 calories. One calorie is the amount of energy required to raise 1 gram of water by 1°C. Thus, 1 kilocalorie is the amount of energy required to raise one kilo of water by 1°C. Since a single calorie is quite small, kilocalories [kcal, Calories (uppercase)] are used for measuring energy contained in the food we eat.

Most of what makes up our food can be broken down into three groups: carbohydrates, fats, and proteins. Each gram of carbohydrate yields roughly 4 Calories, and each gram of fat yields 9 Calories. Proteins actually contain 7 Calories per gram, but because the human body cannot convert all amino acids to usable energy, proteins generally yield about the same 4 Calories that carbohydrates do. It should also be noted that alcohol has 7 Calories per gram.

Some foods are entirely contained by one group. Olive oil, for example, is pure fat. If one were to measure 14.235 grams (approximately 1 tablespoon), it would yield roughly 128.115 Calories, or 14.235 grams olive oil * 9 Calories/gram of fat.

Other foods have different combinations of each. For example, some peas I bought have the following properties per serving:

• 0g fat
• 12g carbs
• 5g protein
• 70 calories total

We can figure out the calories on our own by: (0g * 9Cal/g) + (12g * 4Cal/g) + (5g * 4Cal/g) = 0 Cal + 48 Cal + 20 Cal = 68 Calories, which is rounded up as is allowed by the FDA guidelines.

The balance of these nutrients is also important. It is generally agreed upon that a standard diet should be comprised of roughly:

• 55-70% carbohydrates
• 15-30% fats
• 15-25% proteins

If you eat 65% carbs, 25% fats, then you’d be under your daily protein allotment at 10%. Luckily, these are guidelines. There’s nothing saying you can’t eat more or less of each group. I do often. You will, however, see these figures reflected across many of the world’s cuisines, with some disparity. See for yourself:

• diets around the world (NBC)
  
• how the menu varies (FAS/USDA)
  
• the world’s healthiest diets (Oprah)
• diet secrets from around the world (medicinenet.com)
• what the world eats, part I (TIME Magazine)

Variety is also hugely important in diet in order to get other nutrients such as vitamins, minerals, phytochemicals and enzymes. But that’s another post.