AIM: Nutritional problems in adolescent girls are iron deficiency anemia, thin adolescents, and chronic lack of energy. Banjar district has a prevalence of anemia of 23.54%, the prevalence of thin and very thin adolescents is 9.78% and 2.90%, while the prevalence of chronic energy deficiency is 1.35%. One factor that influences health problems is knowledge. Increased knowledge can be provided through health education. One technique that can carry out health education in adolescents is to conduct counselor intervention. OBJECTIVES: The aim of the study was to know the difference in knowledge, attitudes, hemoglobin (Hb) levels, upper arm circumference, and body mass index (BMI) between before education and after education. METHODS: This study uses a quasi-experimental intervention as adolescent counselors who provide education about nutrition to young women at SMAN 1 Aluh-Aluh. The variables identified were Hb levels, upper arm circumference, and BMI before and after education by the counselor. Education was given in three meetings; each meeting identified the knowledge and attitudes of adolescents about nutrition. The number of samples is 53 people taken by incidental sampling. RESULTS: Knowledge data showed a significant difference before education by the counselor and after the first education (p = 0.000), there was no significant difference after the first and second education (p = 0.533), there was a significant difference after the second and third education (p = 0.000). Attitude data showed that there was no significant difference between attitudes before education and after the first education (p = 0.350), there was no significant difference between the first and second education (p = 0.991), and there was a significant difference between the second and third education (p = 0.000). Hb level data showed that there was no significant difference before counselor education and after education (p = 0.410). Upper arm circumference data showed that there was a significant difference before and after counseling by the counselor (p = 0.019). BMI data showed that there was no significant difference before and after education by counselors (p = 0.418). CONCLUSION: Adolescent counselors can improve knowledge and attitudes about nutrition and increase the size of the upper arm circumference of adolescents in wetland areas.