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Ask Shannon: Fitness and Nutrition Q & A

Posted May 10, 2008 at 12:00 PM by Shannon Clark

Section: Her Nutrition

With years of training under her belt, resident fitness and nutrition expert Shannon Clark is ready to help you on your way to a healthy, informed lifestyle. Got a question? her your inquiries, and be sure to check back every week for the latest Q&A.

Q: I am hearing over and over again that the goal for your protein and fat intake should be about 20-25% fat and then 10-15% protein, if not more.  I am just wondering though if this applies to the average diet or if the percentage of macronutrient breakdown holds the same for higher calorie levels?

A: Great question! I can’t tell you enough how many people make the percentage mistake when trying to figure out their diets.
While percentages are good to go by as a general rule and for helping you ‘eyeball’ your plate, when it comes to determining the exact number of specific macronutrients to consume, it’s best to leave percentages alone and focus on raw numbers.

As you stated, percentages really mean nothing when you don’t take into account total calorie intake.

For example, let’s say we have two 120 pound women, one is 5 feet and another is 5’8”.  Now, the 5’8” woman should definitely not be trying to lose weight, if anything she could gain a few pounds.  The woman who is five feet on the other hand could lose a few pounds if it would make her feel more comfortable.

Now, this 120 pound woman who wants to lose weight should set her calorie intake to about 10-11 X her total body weight (1200 – 1320 calories per day).  10% of that intake leaves us with 120 – 132 calories for protein.

Since protein contains 4 calories per gram, this then means her total protein intake for the day would be 30-33 grams.  Now, it doesn’t take much nutritional knowledge to see that that is clearly not a high enough protein intake.  When dieting, your protein needs actually go up (to prevent the loss of muscle mass tissue), so she should be at the very least getting one gram per pound of body weight (assuming she is exercising).  This would mean she needs 120 grams of protein or 480 calories worth. 

Now if you plug that 480 calories into the total diet and you come up with a percentage value of 36-40%!  That’s a far cry from the 10-15% recommendation!

When it comes to dietary fat, that can be a little more variable.  Some people do exceptionally well on a low-carb diet (so higher fat by corollary), while others do better on a higher carb diet.

How you will determine this percentage is basically what makes you feel most comfortable and allows you to stay within your target calorie range.

A minimum of 15% dietary fat is a good place to start though; anything lower than this and you often run into hormonal issues.

Another important thing to keep in mind here is that in order to stay out of ketosis (which is a metabolic state where the body stops running off carbohydrates for energy and instead runs of dietary fat), you must consume 100 grams of carbohydrates or more per day (this is without any exercise – exercise will demand more).

100 grams of carbs would translate to 400 calories, so again, depending on the total calorie intake, this could be anywhere from 30% of your diet to as little as 10% (for very active males).

So to sum up, my general recommendation is not to use percentages at all regardless of your diet.  They really just don’t hold up when you take into consideration total calorie intakes. 
Instead, figure out your calorie needs, then make sure you are getting at least one gram of protein per pound of body weight (up to a max of 1.5-2 grams per pound – there is really no need to go higher).

Then spread out your carbohydrates and dietary fat how you please while staying with your total calorie intake.

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Tags: caloric intake, clark, diet, dietary fat, fat, ketosis, macronutrient percentages, maintain weight, protein, weight loss

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