Latar Belakang : Usia Remaja adalah usia yang mana terjadi perubahan-perubahan hormonal, baik perubahan dari struktur fisik maupun psikologis. Pada usia remaja banyak sekali perubahan pertumbuhan yang terjadi, missal perubahan massa otot, perubahan hormon dan perubahan pada jaringan lemak. Hal tersebut berimbas pada jumlah kebutuhan gizi remaja yang semakin banyak. Masalah gizi yang masih dialami oleh kelompok usia remaja adalah gizi kurang (underweight) dan obesitas (overweight). Beberapa factor yang dapat mempengaruhi status gizi seseorang adalah asupan energi, aktivitas fisik dan pengetahuan mengenai gizi seimbang.
Tujuan Penelitian : Penelitian ini bertujuan untuk mengetahui hubungan asupan energi, aktivitas fisik dan pengetahuan gizi seimbang dengan status gizi siswa SMA Negeri 8 Semarang.
Metode : Jenis penelitian ini adalah analitik observasional dengan pendekatan cross sectional. Sampel penelitian sebanyak 76 siswa SMA Negeri 8 Semarang dengan menggunakan metode simple random sampling. Data asupan energy diambil menggunakan form Recall 3x24 jam. Data Aktivitas Fisik diambil menggunakan form Physical Activity Level (PAL). Data pengetahuan gizi seimbang diambil menggunakan kuesioner pertanyaan mengenai pengetahuan gizi seimbang. Analisis data menggunakan uji statistik Korelasi Gamma.
Hasil : Karakteristik responden usia 17 tahun 47 (61.8%) siswa dan usia 16 tahun 29 (38.2%) siswa. Perempuan 40 (52.6%) siswi dan kelompok laki-laki 36 (47.4%) siswa. Asupan energi kurang 23 (30,3%), baik 37 (48,7%) dan lebih 16 (21,1%) siswa. Aktivitas fisik ringan 56 siswa (73,7%) dan sedang 20 (26,3%) siswa. Tingkat pengetahuan gizi seimbang kategori baik 49 (64,5%), cukup 12 (22,4%) dan kurang 10 (13,2%) siswa. Status gizi berdasarkan IMT/U responden kategori kurang 24 (31,6%) normal 42 (55,3%) dan overweight/gemuk 10 (13,2%) siswa. Hasil uji menunjukan terdapat hubungan atau relasi yang bermakna antara asupan energi dengan status gizi (p=0,040). Tetapi tidak terdapat hubungan yang berarti antara aktivitas fisik (p=0,379) dan pengetahuan gizi seimbang (p=0,573) dengan status gizi.
Kesimpulan : Terdapat relasi atau hubungan yang berarti (bermakna) antara asupan energi dengan status gizi dengan nilai p 0,040 dengan kekuatan korelasi 0,360 yang menunjukan korelasi positif dengan kekuatan korelasi yang lemah.

ABSTRACT:
Background of Study: Adolescence is an age at which hormonal changes usually occur, such as changes in physical and psychological structures. The period of adolescent growth is marked by many changes including changes in muscle mass, fat tissue, and hormonal changes. These changes affect the nutritional needs of adolescents. Problems of nutrition that are still experienced by adolescent age group are underweight and obesity (overweight). Several factors that can affect a person's nutritional status are energy intake, physical activity and knowledge of balanced nutrition.
The Objective of the Study: This study aims to find out the relationship between energy intake, physical activity and balanced nutritional knowledge with the nutritional status of students at Senior High School 8 Semarang.
Method: This was an observational analytical study with a cross-sectional design. The research samples were 76 students of Senior High School 8 Semarang selected using simple random sampling method. The energy intake data were taken using the 3x24 hours Recall form. The physical activity data were taken using the Physical Activity Level (PAL) form while the data on knowledge of balanced nutrition were taken using a questionnaire about balanced nutritional knowledge. The data analysis used Gamma Correlation statistical test.
Results: Characteristics of the respondents were 47 17-year-old students (61.8%) and 29 16-year-old students (38.2%), 40 female students (52.6%) and 36 male group students (47.4%). The results of the energy intake were 23 students had energy intake deficit (30.3%), 37 students had good energy intake (48.7%) and 16 students had excess energy intake (21.1%). 56 students did light physical activity (73.7%) and 20 students were moderately active (26.3%). The level of knowledge of balanced nutrition in the good category was 49 students (64.5%), 12 students for moderate category (22.4%) and 10 students had less/ poor knowledge (13.2%). Nutritional status based on BMI-for-age of the respondents showed that 24 students were underweight (31.6%), 42 students were normal (55.3%) and 10 students were overweight/obese (13.2%). The test results also showed that there was a significant relationship between energy intake and nutritional status (p=0.040). However, there was no significant relationship between physical activity (p=0,379) and the knowledge of balanced nutrition (p=0,573) with nutritional status.
Conclusion: There was a significant correlation between energy intake and nutritional status with a p-value of 0.040 with a correlation strength of 0.360 showing a positive correlation with a weak correlation strength.