The other complaint is that the medicines must be taken on an empty stomach to facilitate absorption. This can be difficult for patients to follow (for example, shift workers who take their meals at irregular times) and may mean the patient waking up an hour earlier than usual everyday just to take medication. The rules are actually less stringent than many physicians and pharmacists realise: the issue is that the absorption of RMP is reduced if taken with fat, but is unaffected by carbohydrate, protein, or antacids. So the patient can in fact have his or her medication with food as long as the meal does not contain fat or oils (e.g., a cup of black coffee or toast with jam and no butter). Taking the medicines with food also helps ease the nausea that many patients feel when taking the medicines on an empty stomach. The effect of food on the absorption of INH is not clear: two studies have shown reduced absorption with food but one study showed no difference. There is a small effect of food on the absorption of PZA and of EMB that is probably not clinically important.