To study the diet of a sample of peasants from Calakmul, Campeche, Mexico who suffered seasonal changes in body composition, we conducted an observational study of dietary patterns over 24-hour periods made at 15-day intervals during the 2001-2002 agricultural cycle. The study was complemented with a list of locally hunted, harvested or gathered foods, obtained from key informant interviews in 2018. Significantly more Kilocalories (Kcal) were obtained from the local environment than from store-purchased foods in both seasons, emphasizing the dietary importance of local subsistence production over commercial endeavors. There were no Kcal differences between seasons. Food obtained from agricultural plots, backyards and woodlands offered a balanced diet, but diversity was greater during the abundance season. The results suggest that the reported weight loss during the scarcity season is not due to a lack of food, but to the deterioration of the diet ́s complementarity which store foods are unable to compensate for.