An isolated monoclonal bispecific antibody, or an antigen-binding portion thereof, that binds to beta-Klotho and Fibroblast Growth Factor Receptor 1c (FGFR1c), comprising: (a) a first arm comprising: (i) a heavy chain variable region CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 15, a heavy chain variable region CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 31, a heavy chain variable region CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 47, a light chain variable region CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 62, a light chain variable region CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 78, and a light chain variable region CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 93; and (b) a second arm comprising: (i) a heavy chain variable region CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 136, a heavy chain variable region CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 137, a heavy chain variable region CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 138, a light chain variable region CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 139, a light chain variable region CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 140, and a light chain variable region CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 141. (a) a first arm comprising: (i) a heavy chain variable region CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 15, a heavy chain variable region CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 31, a heavy chain variable region CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 47, a light chain variable region CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 62, a light chain variable region CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 78, and a light chain variable region CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 93; and (i) a heavy chain variable region CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 15, a heavy chain variable region CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 31, a heavy chain variable region CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 47, a light chain variable region CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 62, a light chain variable region CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 78, and a light chain variable region CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 93; and (b) a second arm comprising: (i) a heavy chain variable region CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 136, a heavy chain variable region CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 137, a heavy chain variable region CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 138, a light chain variable region CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 139, a light chain variable region CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 140, and a light chain variable region CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 141. (i) a heavy chain variable region CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 136, a heavy chain variable region CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 137, a heavy chain variable region CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 138, a light chain variable region CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 139, a light chain variable region CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 140, and a light chain variable region CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 141.