by Marion Nestle
May 1 2012

Nutritionist’s Notebook: Estimating nutrient requirements

My Tuesday question from student readers of NYU’s Washington Square News:

Question: How can we determine our individual caloric, vitamin, carbohydrates, fats and other intake requirements per day based on our own individual weight, height and lifestyle?

Answer: You can’t. You will have to be satisfied with estimates based on measurements performed years ago on a small number of study subjects.

We require calories and nutrients — 40 to 50 separate substances that our bodies cannot make, we must get from food. Because these interact, studying one at a time gives results that may well be misleading.

Early nutrition scientists got “volunteers”— in quotes because study subjects often were prisoners — to consume diets depleted in vitamin C, for example. They waited until the subjects began to develop scurvy, a sign of vitamin C deficiency. Then they fed the subjects the smallest amount of vitamin C that would eliminate symptoms.

Because individuals vary in nutrient requirements, scientists used this data to estimate the range of nutrient intake that would meet the needs of practically everyone.

The Institute of Medicine compiles such data into Dietary Reference Intakes and presents the estimates by sex and age group. You can look up your requirements in DRI tables. DRIs account for the needs of 98 percent of the population. If your requirements are average, you will need less.

Few American adults show signs of nutrient deficiencies, but if you are worried about your own intake of nutrients, you can take a multivitamin supplement. Note, however, that we have no evidence to show supplements make healthy people healthier.

You can estimate calories by looking up everything you eat or drink in food composition tables, but it is easier to weigh yourself at regular intervals. If you are gaining weight, you are eating too many calories for your activity level.

With nutrition, it’s best to get comfortable with estimates and probabilities.

Fortunately, eating a healthy diet takes care of nutrients without your having to give them a thought. Eat your veggies!

A version of this article appeared in the Tuesday, May 1 print edition. Marion Nestle is a contributing columnist. Email her questions at

  • Marion: This is highly insightful. Do the the Harris-Benedict and Mifflin equations to calculate daily caloric intakes fall under this category?

  • I agree, if you eat well there’s no need to calculate nutrient requirements. There’s no need to calculate calories or grams or points either. Your innate intelligence will take care of it. I would add that in addition to eating lots of veggies, eat moderate amounts of grass fed meat and poultry, wild or sustainably farmed fish, pastured eggs and raw nuts and seeds.

  • I’ve been taking supplements for awhile now and in quantities that are a fair bit as part of my nutrition plan. I do take some stuff extra to help with a back injury but overall, I do find that when I take supplements, I actually see changes in my overall well-being and I’m less prone to getting sick.

    I do find that I have to rotate my supplements every 3 months and take a healthy dose of probiotics as well.

    The most obvious sign of improvements is when I take calcium and magnesium tablets (2-in-1). My nails are stronger and my hair longer. Having said that, if I exercise really hard, my nails and hair also tend to grow faster too! 🙂

  • When ever i gain weight i stop eating carbs and start eating fruits and vegetables.. i come back to my weight of 70 Kg.This article is nice.

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