Sunday, July 5, 2009

Do Nutrient Needs Decrease as Calorie Intake Decreases?

Hi,
Thanks for your educational blog.
I am wondering about daily nutrition charts. Common sense tells me one thing but I might be wrong.
I've seen a chart for a 2000 calorie daily target that has all the amounts for the nutrition label from fats down to the vitamin %. If I want to lose weight following a 1200 calorie plan, don't the other amounts also go down? Is there a set recommendation on this or would it be for the individual?
Thanks so much....
Joyonya,
Bonnie

Dear Bonnie,

The charts you see with nutrient recommendations for a person eating 2000 calories per day were developed for use on food labels. The Daily Reference Intakes (which have essentially replaced the Recommended Dietary Allowances) tell how much of each nutrient is recommended based on gender and age. Since the food labels can't speak to each person and include children, nursing moms, athletes, and mature adults all in one small chart, the Daily Values were established: These are the levels you see on the food labels and are recommended for the average person who consumes about 2000 calories per day.

Recommendations for different nutrients for the average adult woman are not differentiated based on weight or activity level. Basically they are just averages taken from studying a group of women to see how much is needed to maintain normal body functioning and healthy tissue stores. Different people may need slightly different levels regardless of their weight or activity--just based on individual body chemistry--so the recommendations take all this into account and add a margin of safety as well.

The only nutrients that change based on calorie intake are some of the B vitamins which are used to metabolize carbohydrates. The more you eat, the more of these nutrients you need to metabolize what you're eating. As a woman, you still need the same levels of vitamin C, iron, calcium, etc regardless of whether you are on a weight loss diet or not.

As you reduce your calorie intake, the percentage of calories from protein, carbohydrates, and fats remains the same; the actual number of grams will be reduced since the total figure is smaller. The same recommendations stay for grams of fiber, regardless of your calorie intake.

Probably the safest way to assure you are getting the required nutrients on such a low calorie intake is to take a basic vitamin/mineral supplement that supplies close to 100% of the daily values and an additional calcium supplement (as the amount required cannot fit into a tiny pill). Another way is to follow the food pyramid guidelines so you are getting a variety of nutritious foods.

Here is the food pyramid website: http://www.mypyramid.gov/
and here is information on nutrient needs for each gender and age group from the USDA: http://fnic.nal.usda.gov/nal_display/index.php?info_center=4&tax_level=2&tax_subject=256&topic_id=1342

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