Disclosed are a novel pharmaceutical composition, a food or beverage, and methods related to these products. The pharmaceutical composition is characterized by comprising the following protein (I) or (II) as an active ingredient: (I) a macrophage apoptosis inhibitor: and (II) a protein which consists of an amino acid sequence having deletion, substitution or addition of one or more amino acids in the amino acid sequence of the macrophage apoptosis inhibitor and having homology with the aforementioned amino acid sequence, and has a function of inhibiting differentiation of preadipocytes into mature adipocytes and/or a function of inducing lipolysis in the mature adipocytes. The pharmaceutical composition contains as an active ingredient, for example, a protein consisting of an amino acid sequence set forth in SEQ ID NO: 1, a protein consisting of an amino acid sequence set forth in SEQ ID NO: 5, or a mutant protein of any one of the aforementioned proteins which is so mutated that a function of inhibiting the differentiation of a preadipocytes into mature adipocytes and/or a function of inducing lipolysis in a mature adipocytes cannot be impaired.
