Lemon and honey combine to make an effective and delicious digestive tonic, especially after you've eaten a greasy meal. Lemons are low calorie. Honey is fat free and a natural energy booster. The combination of the two is an effective fasting treatment. When you have a cold or flu, getting plenty of fluids and eating foods rich in vitamins A and C can help restore your immune system and help you heal more quickly. Lemons contain both vitamins as well as anti-inflammatory properties. Honey soothes your throat and inhibits certain infection-causing bacteria.