Dogs aren't usually fussy eaters, so anything in his path is likely to be taste tested, the skirting boards, doors, bedding, toys table scraps, garbage or grass. Only thing I found my dogs won't eat is lettuce..
Dogs are primarily carnivores (meat eaters) but can also survive well on a vegetarian diet, unlike cats who may die without animal protein..
Like all living creatures a dog needs a good healthy combination of proteins, carbohydrates, fats, vitamins, minerals and water as part of a good healthy balanced diet and should provide enough calories to meet the daily requirements.
No-one is actually sure why dogs eat grass, although there are many theories on the subject.
Dogs descend from Canidae ( wolves and foxes ) when hunting they would eat the entire "kill", which means they would consume many herbivores ( plant eating animals ) so the wolves and foxes would end up eating a lot of plants, berries, vegetation and fruits that were found in the stomach and intestines of their pray and what is quite interesting Is the fact the carnivores (meat eaters) would eat the stomach contents first, so it's very likely that dogs may eat grass as its part of their natural diet.
Do dogs eat grass because they make themselves vomit.. or do they vomit because they eat grass. Most veterinarians believe that dogs simply eat grass because they like it and vomiting naturally follows. When eaten the grass will act as an irritant which causes vomiting. Are they smart enough to use grass as a medicine? I don't think we are smart enough to know the answer to that question.
I have seen it all over the years with my dogs. Dogs that have never eaten grass until they are ill, dogs that see it as free food, dogs that have never touched it. Dogs that would go on a walk and only eat the long grass and dogs that believe they are the next generation flymo. So I have no answer either.
Some veterinarians believe that dogs eat grass because their diets are lacking in greens, so will eat grass to compensate. Sometimes dogs will seek out only certain varieties of grass to nibble. Some believe they are lacking in certain vitamins or minerals.
But no matter for what reason your dog's "grass" habit is normal behaviour.
A NOTE OF CAUTION
Take extra care that your dog Is not eating grass that has been fertilised with fertilisers or pesticides nor treated with lawn care. As this could upset the stomach or even worse.
Check your choice of dog walking area is safe and not recently been treated.