Full of nutrients as they are, says Verona, certain vegetables, especially cruciferae (e.g. broccoli, cauliflower, Chinese white cabbage, etc.), have fibre that is not easily digestible. They need to be broken down, fermented and absorbed through intestinal enzymes; this process may cause bloating or flatulence. Thus, these vegetables are best avoided by people with weak gatrointestinal functions. Last but not least, even though vegetables can help us guard against constipation, we should also ensure an adequate level of fluid intake for this purpose.

Table 2 Energy, proteins, carbohydrates, total fats, saturated fats, potassium, sodium and fibre content of selected gourds and vegetables

Food item (Per 100g)	Calories (Kcal)	Protein (g)	Carbohydrates (g)	Fats (g)	Saturated fats (g)	Potassium (mg)	Sodium (mg)	Fibre (g)
Tomato	20	0.9	4	0.2	0	163	8	0.5
Green pepper	20	0.86	4.64	0.17	0.058	175	3	1.7
Red pepper	31	0.99	6.03	0.3	0.027	211	4	2.1
Yellow pepper	27	1.00	6.32	0.21	0.031	212	2	0.9
White gourd	12	0.4	2.6	0.2	NA	78	1.8	0.7
Pumpkin	26	1.00	6.5	0.1	0.052	340	1	0.5
Cucumber	16	0.8	2.9	0.2	NA	102	4.9	0.5
Eggplant	18	1.0	3.0	Trace	0.026	220	0	2.6
Bitter gourd	7.4	0.7	1.0	ND	0	190	3	2.2
Sponge gourd	21	1.0	4.2	0.2	0.016	115	3	0.6
Zucchini	17	1.21	3.11	0.32	NA	261	1	1
Lettuce	10	1.0	1.1	Trace	0.029	230	8	Trace
Spinach	14	2.3	0.3	0.4	0.04	558	5	1.7
Water spinach	27	2.9	1.0	0.5	0	312	25	2.8
Amaranth (Chinese spinach)	13	1.9	0.48	0.4	0.048	480	15	2.0