Q. I’ve heard bone broth is good for weight loss. Is this true? If so, why?

A. Judith C. Thalheimer, RD, LDN, managing editor of Tufts Health & Nutrition Letter, answers: “Bone broth is made by simmering animal bones in water and a small amount of an acid like vinegar. The acid helps dissolve the bone, releasing collagen and minerals into the water. The protein collagen is a key component of connective tissue, so it has been suggested consuming collagen is good for skin and joints, but science does not support these assertions. Collagen is not absorbed directly, because proteins are broken down into their component amino acids before absorption.

“A trendy diet book may be behind the false impression that drinking bone broth is good for weight loss. This questionable diet program does include drinking broth (homemade or purchased from the author for $128 a case), but it is also a low-carb, Paleo-style diet that includes two mini fast days on which adherents consume only around 500 calories in a day.That is likely to be responsible for any weight loss seen with this program.

“Some sources claim bone broth is a protein-rich food that helps cut calories because protein helps us feel satisfied longer. First, fiber is much more closely tied to satiety than protein, and bone broth has no fiber. Second, while bone broth has more protein than regular beef or chicken broth, it is far from a high-protein food. Even a cup of commercially-available bone broth to which extra collagen has been added provides only 15 grams (g) of protein—less than the 17 g found in just six ounces of Greek yogurt, and far less than what you’d get from a three-ounce serving of pot roast or chicken.

“Drinking water or consuming broth-based soup before a meal has been shown to reduce calorie intake at that meal, so bone broth could be helpful in that way (but so could a glass of water).”