First trimester nausea is associated with gastric slow wave dysrhythmias (tachygastria, bradygastria). We tested the roles of meal composition and caloric content on nausea and slow wave rhythm in 14 nauseated pregnant women. Electrogastrography quantified dysrhythmic activity and signal power responses to meals. Symptomatic women reported mild to moderate nausea and exhibited increased dysrhythmias during fasting (P < 0.05). Protein-predominant meals reduced nausea and dysrhythmic activity to greater degrees than equicaloric carbohydrate and fat meals and noncaloric meals (P < 0.05). Meal consistency did not affect symptom responses, although liquid meals decreased dysrhythmias more than solids (P < 0.05). Carbohydrates and fats increased electrogastrographic power to similar degrees as proteins, whereas responses to noncaloric meals were less. In conclusion, protein meals selectively reduce nausea and gastric slow wave dysrhythmias in first trimester pregnancy. Meal consistency is a limited factor in the favorable effects of protein. Electrogastrographic power changes do not explain the symptom response to protein. Thus dietary modulation of gastric myoelectric rhythm with protein supplementation may provide symptomatic benefit in nausea of pregnancy.