Table 4.

Difference in energy intake (kJ) of different food groups and Lin's concordance correlations (LCC) between the self-administered web-based and the interviewer-administered telephone-based 24-h dietary recalls (n 514)

(Mean values and standard deviations, proportional differences and LCC)

	Web-based 24-h recalls		Telephone-based 24-h recalls		Difference between both recall methods				LCC
	Mean	sd	Mean	sd	Mean	sd	%*	P
Alcoholic beverages	465	583	462	521	3	444	0·4	0·88	0·68
Bread	1493	669	1518	665	−25	513	−3·5	0·27	0·70
Cereal products and binding agents	433	573	471	476	−38	576	−5·3	0·14	0·40
Cheese	435	336	509	358	−74	371	−10·4	<0·0001	0·42
Coffee, tea and water	21	14	73	157	−52	155	−7·3	<0·0001	0·02
Composite dishes	253	488	254	446	0	662	−0·0	1·00	0·00
Eggs	87	128	88	129	−1	144	−0·1	0·89	0·38
Fats, oils and savoury sauces	530	361	647	351	−118	424	−16·5	<0·0001	0·28
Fish	134	248	177	278	−43	327	−6·0	0·00	0·23
Fruit	419	356	461	340	−43	321	−6·0	0·00	0·57
Fruit/vegetable juices, soft drinks	200	259	237	278	−36	250	−5·1	0·00	0·56
Legumes	35	105	30	103	5	127	0·7	0·35	0·25
Meat, meat products and poultry	661	515	725	488	−64	576	−8·9	0·01	0·34
Milk and milk products	698	436	779	465	−81	404	−11·3	<0·0001	0·59
Nuts, seeds and snacks	429	520	462	542	−32	554	−4·5	0·19	0·46
Pastry, cake and biscuits	612	530	616	501	−4	589	−0·6	0·86	0·35
Potatoes	309	333	309	322	0	418	−0·0	0·99	0·19
Savoury sandwich fillings	75	168	67	150	8	153	1·1	0·25	0·54
Soups	89	142	77	138	11	176	1·6	0·14	0·21
Soya and vegetarian products	57	151	65	160	−7	142	−1·0	0·25	0·58
Sugar and confectionery	390	365	482	420	−92	409	−12·9	<0·0001	0·45
Vegetables	162	119	189	125	−26	137	−3·7	<0·0001	0·36

^*Proportional difference is calculated as ((mean of web-based 24 h recall) – (mean of telephone-based 24 h recall))/(mean difference in kJ) × 100. The mean difference between the methods is −714 kJ (Table 2).