The sugar alcohols (malitol, sorbitol, lalctitol, erythritol and others are only slightly digested by humans (but the colonic bacteria just LOVE the stuff- and cause us cramps and runs.) I truly hate these things, ESPECIALLY MALTITOL, which gives me a headache AS I EAT IT and THEN causes the cramps. It's the most common of these "foods" in fake chocolates and "no sugar added" chocolate ice cream.
They go from available 1 to 3 calories/gram instead of the normal 7 for fully absorbed ethyl alcohol.
To the extent of their caloric impact, I would GUESS that they react very much like ethyl alcohol, but a net less effect than a gram of the REAL STUFF (pass the Beefeater!

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Erythritol is in a class of it's own with only .2 calories per gram and thus probably has NO effect on triglycerides...or weight! It's not nearly so common as the others.