The "stone age pancreas" theory asserts exactly that. People who went into their zone's food-scarcity-time storing fat like bears could coast through some inevitable food delays until spring.

Later, when we gathered enough to have infectious disease problems, having enough fat to burn off a serious infection with high fever and disrupted digestion was another survival factor.

And I don't need a genetic test to know how carbohydrates affect me. The lower I go, the better my body currently likes it