why do fish and birds have less calories than cows and pigs?

Question

why do fish and birds have less calories than cows and pigs?

In: Biology

Answer 1

Calories come from 3 different substances. Fat, protein, and carbs. Both protein and carbs contain 4 calories per gram and fat contains 9 calories per gram. You can do the math yourself using a nutrition facts label (though nutrition labels have some rounding rules that could have your math off by 2-5 calories).

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So to answer the question, fish and birds are typically less fatty than beef and pork and thus have fewer calories per gram.

Answer 2

Red meat (beef, pork, etc) has a higher fat content and therefore more calories than fish and poultry.

Answer 3

It depends from the source.

Wild animals are on average more lean than farmed ones.

A poultry factory chicken could have more calories per gram than a wild deer, so to say.

First example that comes to mind are ancestral foi gras geese. The method was to nail the goose feet to the ground and feed it 24/7 through a funnel directly shoved into its stomach.

No movement, only feeding.