Homeostasis protein berperan penting dalam memperlambat proses malnutrisi dan dalam mempertahankan massa bebas lemak pasien kanker. Kehilangan signifikan massa bebas lemak terutama massa otot skelet akan mengurangi mobilitas fisik, kapasitas fungsional, dan skor kualitas hidup pasien kanker. Penelitian ini merupakan studi potong lintang yang bertujuan untuk mengetahui korelasi antara asupan protein dengan massa bebas lemak dan kapasitas fungsional pada pasien kanker paru di poli onkologi RS Persahabatan Jakarta. Didapatkan 52 subjek laki-laki dengan rerata usia 55,63 6,77 tahun. Jenis dan stadium kanker yang terbanyak ditemukan adalah adenokarsinoma 63,5, stadium IV 65,4. Status nutrisi kurang berdasarkan IMT ditemui pada 21,2 subjek, dan berdasarkan kadar albumin serum didapatkan 30,8 subjek dengan hipoalbuminemia. Lebih dari 50 subjek dengan asupan energi dan protein dibawah rekomendasi asupan untuk pasien kanker. Pada pemeriksaan komposisi tubuh didapatkan rerata massa bebas lemak 47,20 6,28 kg, dengan 48,1 indeks massa bebas lemak rendah, massa otot rerata 44,74 5,98 kg dengan 40,4 massa otot tergolong kurang. Nilai kapasitas fungsional skala Karnofsky.

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The homeostasis of protein plays an important role in decreasing the process of malnutrition and in maintaining fat free mass in cancer patients. The significant loss of fat free mass, especially skeletal muscle mass could decrease physical activity, functional capacity, and quality of life of cancer patients. This was a cross sectional study aimed to investigate the correlation of protein intake, fat free mass and functional capacity in lung cancer patients in the Oncology Unit of Persahabatan Hospital Jakarta. Obtained 52 male subjects with a mean age of 55,63 6,77 years old. The most cancers type were adenocarcinoma 63,5 and most of subjects were at stage IV 65,4 . Nutritional status of the subjects 21,2 were in undernutrition based on body mass index parameter, and 30,8 of the subjects were in hypoalbuminemia. More than 50 of the subjects had low energy and protein intake. The mean of fat free mass was at 47,20 6,28 kg, that 48,1 of fat free mass index were in low categorized, and 40,4 of muscle mass were also in small categorized, that the mean was at 44,74 5,98 kg. Functional capacity Karnofsky scale of the subjects 26,9 showed less than 70. The data showed that the subjects had nutrition problems. This study showed positive and significant correlations between protein intake with fat free mass index r 0,379, p