Lamb is healthy, high in protein and fats and doesn't contain any FODMAPs.
Remember to avoid adding high FODMAP foods while cooking.
Lamb, hogget, and mutton, generically sheep meat, are the meat of domestic sheep, Ovis aries.
A sheep in its first year is a lamb and its meat is also lamb. A sheep in its second year and its meat are hogget. Older sheep meat is mutton. Generally, "hogget" and "sheep meat" are not used by consumers outside New Zealand and Australia, only the industry.
In South Asian and Caribbean cuisine, "mutton" often means goat meat. At various times and places, "mutton" or "goat mutton" has occasionally been used to mean goat meat.