Introduction: Patients who are diagnosed with cancer are subjected to different nutritional maladies, such as malnutrition, sarcopenia, and cachexia that have prognostic values.

Objective: The aim of the present study is to evaluate the prevalence of nutritional alterations in subjects with cancer.

Methods: The study has a cross-sectional design. Adult volunteers of both sexes were recruited and then underwent medical and nutritional assessments at the ambulatory oncology service. Diagnoses of sarcopenia and cachexia were
made according to international criteria.

Results: A total of 119 subjects were recruited, 57.1% were women. The mean age was 55.9 ± 14.2 years, and the mean body mass index was 25.0 ± 4.88 kg/m2. Of the total population studied, 25.2% had breast cancer, 17.6% gastrointestinal cancer, and 16.8% hematologic cancer and other neoplasms. According to the WHO guidelines for body mass index, 14% of subjects were underweight, 40% had normal weight, 30% were overweight and 16% were obese. The prevalence of sarcopenia was 26.1%; we observed that male volunteers had a higher risk of presenting sarcopenia [OR 13.1 (IC 95% 4.5-37.9, p<0.001)] and 47.6% of those subjects had gastrointestinal cancer [OR 3.3 (IC 95% 1.3-8.9,
p<0.05)]. Finally, 12% of all of the subjects were diagnosed with cachexia.

Conclusion: The prevalence of malnutrition, sarcopenia, and cachexia are high in oncological patients treated in the ambulatory service, especially in men and in those diagnosed with gastrointestinal cancer.