Table 4.

Combination of methodologies for food waste studies conducted in the National School Lunch Program (visual estimation, digital photography, direct weighing)^a

	Reference
	Comstock and colleagues, , 198155	Graves and colleagues, , 198356	Templeton and colleagues, , 200557	Wallen and colleagues, , 201158	Gase and colleagues, , 201459	Hanks and colleagues, , 201460	Taylor and colleagues, , 201461	Schwartz and colleagues, , 201562
Study design	CSbc	CSc	CS	CSc	CS	CSc	CSc	Ide
Specific data collection method	Wf VOg	Wh VOi	Wh DPjk	Wh VOi	W VOi	W VOi DPk	Wh DPk	Wh DP
Type and no. of schools
Elementary	5	1		2		1	2
Middle			3		4			12
Grade level	Kindergarten-6	1–6	6	4	NRl	Kindergarten-5	3–5	5–7
Average percent wasted for dietary components measuredm
Grains/bread	◇n	◇		◇		◇
Vegetables	◇	◇		◇	◇	◇	◇	51
Fruits/fruit juice	◇	◇		◇	◇	◇	◇	31
Meat/meat alternate	◇	◇
Milk	◇			◇		◇		45
Other	◇o	◇o	◇p	◇o		◇o	◇o	26o
Days of food waste data collectionq	4	8	24	1	20	1	8	36
No. of waste observationsr	2,000	450	743	125	2,228	197	276	1,340
Effective public health practice project quality rating10	Weak	Weak	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate

^aData were collected to assess food waste after new school lunch meal patterns were implemented beginning 2012.

^bCS=cross-sectional.

^cCross-sectional study used for validation purposes.

^dI=intervention.

^ePre-post intervention.

^fW=direct weighing.

^gVO=visual observation.

^hDifference weight of plate waste for each food minus weight of average selected serving.

ⁱQuarter waste method (none, half, three-quarters, or all).

^jDP=digital photography.

^kEstimate percent of food selected and plate waste in photograph compared with reference photograph or a sample tray.

^lNR=not reported with specificity.

^mIn some cases, the average percent waste within a dietary component was reported within the cited article. In other cases, this study’s authors calculated average percentage wasted within a dietary component when research design collected waste across multiple intervention periods. When percent consumed was reported (instead of percentage waste), this study’s authors calculated average percetage waste by subtracting the percentage consumed from 100% and, when necessary, averaged across multiple intervention periods or groups.

ⁿ◇=Study indicated dietary component measured but not average percentage wasted within dietary component.

^oMeasured waste of a mixed entrée.

^pSpecific macro- and/or micronutrients measured in whole meal.

^qData calculated as number of days reported for study multiplied by number of schools involved in food waste collections.

^rData reported according to study as individual food items or entire student tray.