Last week’s article discussed the four major components of a food label: total calories, carbohydrates, and protein. The remaining group, fat, is a bit misunderstood. Fat is necessary for its fat-soluble vitamin content and as a source of calories to avoid eating too many calories from carbohydrates, which can raise your blood sugar to abnormal levels.

First, a little chemistry about fats. A fat molecule is three fatty acid molecules joined together. A fatty acid is basically a long string of carbon atoms. Some fatty acids are just a simple string of carbon atoms attached with a simple bond to other carbon atoms. These are called trans or saturated fats. They’re the bad guys, as they promote atherosclerosis or buildup of fat and cholesterol in the blood vessel walls. They also promote the development of certain cancers.

Another group of fatty acids (which become fat when 3 of them are stuck together) has one or more carbon “double bonds”.  A double bond is when two carbon atoms are joined together with twice the bonding energy. These are called mono or polyunsaturated fats; they are the good guys, as their double bond makes their molecule “crooked,” which prevents the fatty acids from being packed close together and, hence, having less density.

Using a 170-pound individual as our model, his/her daily calorie requirement is 170 x 15 = 2,550 calories.  Of that amount, 30% on average should be supplied by total fat eaten, but to be healthy, only a third of this amount can come from the bad guys, i.e., trans and saturated fat. To keep the math simple and counting food value even easier, daily saturated fat intake for our 170-pound patient needing 2,550 calories, when multiped by 0.1 (one third of 30%) equals 255 calories. Divide the 255 by 9 (9 calories/gram of fat) for a result of 28 grams of saturated fat/day. An even easier calculation is your weight x .15  = total grams of saturated fat/day.  Counting grams of allowed saturated fat will keep you within limits of total fat intake.

Fat content of various foods is readily available on the internet but here are a few examples with total fat listed first and saturated fat listed second:

  • 1 cup whole milk = 8 g. total, 5 g saturated.  2% milk = 5 g total, 3 g saturated
  • 1 cup cooked oatmeal =  3.5 g total, only 0.6 g saturated
  • 8 oz. trimmed sirloin steak = 14g total fat, 5g saturated fat.
  • 8 oz. trimmed ribeye steak = 24 g total fat, 11g saturated.

Notice: plant foods have a lot less saturated fat than animal foods.

In summary, calculate your daily allowed saturated fat. Then, add up your different foods eaten with their saturated fat content. The numbers hopefully will be small (usually less than 35), easy to remember give you your maximum daily fat intake.  By default, a high saturated fat intake will also yield a high total fat intake.

Dr. Charlie Barnett contributes to KnoxTNToday, where he writes the weekly column DocTalk, sharing his expertise in health and wellness. He is currently in private practice, focusing on longevity and precision medicine at NovaTheros.

Enjoyed this article? Read more DocTalk columns by Dr. Charlie Barnett.

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