We’ve heard it for years, perhaps even decades, we must reduce our fat consumption. Fat in our diet is a leading cause of obesity and heart disease, plus it contributes to cancer, diabetes, MS, and every other gross disease we want to avoid. But fat is in most foods, outside of fruits and vegetables, so how do we know how much is too much?

A simple rule of thumb is to not eat foods where 30% of their caloric content is fat.

How do we figure out the fat content of a food? Look at the label and do a little bit of math. Each gram of fat contains 9 calories. Multiply 9 by the number of grams of fat on the label. Then divide that number by the number of calories per serving. If the percentage is greater than 30% you should reconsider eating that food (or fake food really, as packaged foods are rarely real, wholesome food).

Here’s an example: Lays Potato chips are marketed as the low fat chip. In fact, they only have 10 grams of fat per serving! Wow! But, if you are enlightened as you are now, you know that the 10 grams of fat is actually 90 calories of fat (9 calories x 10 grams of fat). There are 180 calories per serving; therefore the lays potato chips have 90 fat calories per serving, which is 50%! Lays potato chips don’t look so great now.

The easiest way to avoid eating too much fat is to eat real, live, wholesome food. If the food is packaged, and has a label, you can probably count on it not being that great for you.