Assessment of Dietary Intake and Methods of Diet Survey

Assessment of Dietary Intake

• Household inquiries, or
• Individual food consumption surveys

Methods of Diet Survey

(i) Weighment of Raw Foods

• This is the method widely employed in India as it is practicable and, if properly carried out, is considered fairly accurate.
• The survey team visits the households and weighs all food that is going to be cooked and eaten, as well as that which is wasted or discarded.
• The duration of the survey may vary from 1 to 21 days, but commonly 7 days, which is called "one dietary cycle".

(ii) Weighment of Cooked Foods

• Foods should preferably be analyzed in the state in which they are normally consumed.
• However, this method is not easily acceptable among people and is therefore less commonly used.

(iii) Oral Questionnaire Method

• This method is useful in carrying out a diet survey of a large number of people in a short time.
• Inquiries are made retrospectively about the nature and quantity of foods eaten during the previous 24 or 48 hours.
• If properly carried out, this method can give reliable results.
• A diet survey may also include collection of data relating to dietary habits and practices.

Translation and Analysis of Data

• (a) Mean intake (grams) of food in terms of cereals, pulses, vegetables, fruits, milk, meat, fish, and eggs
• (b) Mean intake of nutrients per adult man value or "consumption unit"

Uses / Importance of a Diet Survey

1. Information about dietary intake patterns and specific foods consumed
2. Estimated nutrient intakes
3. Indication of relative dietary inadequacies as judged by present standards
4. Valuable information for planning health education activities
5. Assessment of the extent and nature of changes needed in agriculture and food production industries

Indirect Method - Food Balance Sheet

• Estimate refers to the country as a whole - conceals regional and group-level differences
• Cheaper and simpler than direct assessment methods
• Gives an indication of the general pattern of food consumption in the country

Park's Textbook of Preventive and Social Medicine, Chapter on Nutrition - Assessment of Dietary Intake (Section 5), pp. 745-746

Exact Text from Park's SPM - Page 745-746

"The value of nutritional assessment is greatly enhanced when it is supplemented by an assessment of food consumption. Direct assessment of food consumption involves dietary surveys which may be household inquiries or individual food consumption surveys."

(i) WEIGHMENT OF RAW FOODS: This is the method widely employed in India as it is practicable and if properly carried out is considered fairly accurate. The survey team visits the households, and weighs all food that is going to be cooked and eaten as well as that which is wasted or discarded. The duration of the survey may vary from 1 to 21 days, but commonly 7 days which is called "one dietary cycle".

(ii) WEIGHMENT OF COOKED FOODS: Foods should preferably be analyzed in the state in which they are normally consumed, but this method is not easily acceptable among people.

(iii) ORAL QUESTIONNAIRE METHOD: This is useful in carrying out a diet survey of a large number of people in a short time. Inquiries are made retrospectively about the nature and quantity of foods eaten during the previous 24 or 48 hours. If properly carried out, oral questionnaire method can give reliable results. A diet survey may also include collection of data relating to dietary habits and practices.

"The data that is collected have to be translated into (a) mean intake (grams) of food in terms of cereals, pulses, vegetables, fruits, milk, meat, fish and eggs, and (b) the mean intake of nutrients per adult man value or 'consumption unit'. This exercise requires the use of suitable tables of food composition. An excellent guide for carrying out this analysis is the ICMR publication: 'Nutritive Value of Indian Foods'."

"A diet survey provides information about dietary intake patterns, specific foods consumed and estimated nutrient intakes. It indicates relative dietary inadequacies as judged by present standards. Not only will such information be valuable for planning health education activities, but it will also allow an assessment to be made of the extent and nature of changes needed in the agriculture and food production industries."