College　students＇　health　and　behavioral　issues　are　gaining　increasing　global　attention,　with　the　optimization　and　choices　of　dietary　structure　becoming　key　factors　affecting　their　physical　and　mental　development.　This　study　examines　adolescents　to　explore　the　impact　of　dietary　habit　changes　on　their　physical　health.　First,　we　investigated　the　factors　influencing　dietary　habit　changes　after　students　entered　college　through　questionnaires.　Based　on　the　theory　of　planned　behavior,　we　constructed　a　structural　equation　model　and　found　that　perceived　behavioral　control　had　the　greatest　impact　on　college　students＇　dietary　choices.　In　addition,　we　investigated　the　patterns　of　dietary　changes　among　adolescents　and　conducted　an　observational　experiment　on　the　impact　of　dietary　changes　on　physical　fitness.　The　results　divided　participants　into　three　groups:　those　reducing　high-calorie　food　intake,　those　increasing　fiber　intake,　and　those　reducing　high-fat　and　high-salt　food　intake.　The　findings　showed　that　reducing　high-calorie　food　intake　had　the　most　significant　effect　on　students＇　physical　health,　resulting　in　a　7.5%　improvement.　Increasing　fiber　intake　followed　with　a　5.68%　improvement,　while　reducing　high-fat　and　high-salt　intake　led　to　a　5.48%　improvement　in　physical　health.　This　study　suggests　that　creating　a　supportive　environment-within　society,　schools,　and　families-can　encourage　healthy　eating　habits　among　adolescents.