Learning the "Real" Phe Content of Potatoes

CONCEPT: Calculating Phe



Participants estimate the amount of phe in an assortment of potatoes, then use a gram scale and a food list to calculate actual phe content.



To improve knowledge of portion sizes and phe values by comparing estimates to actual values.



Gather an assortment of potatoes and potato products. Suggestions are provided on the worksheet, but make sure to include foods the participants might typically eat.

Complete the worksheet
Distribute a worksheet to each participant.
Explain: For each potato or potato product:

  • Estimate the serving size: Is it a small, medium, or large serving?
  • Estimate the weight: How many grams does it weigh?
  • Estimate the phe content: How many milligrams of phe does it contain?


  • Weigh the potato
  • Calculate the amount of phe in the serving, using the food list

When the participants have finished, discuss theirs results.
Compare the estimates to the actual values.
How far off were the estimates?
How would the difference affect a food record?
Were any of the portion sizes too big? (How would they fit into your food pattern/phe limit?)
What are some strategies for making accurate estimates?





[top of page]