In late 1960’s, my Aunt would buy two quart bottles of Pepsi per week as a treat to her kids, in a household of four people. No one drank 16 oz. beverage then. More likely 6 or 4. Poured over ice it was a treat. My mom and Grandmother too... Did not spring for that. Lucky to have the Safeway brand Hawaiian punch soda.
We did not have the western diet that we do now until a few decades ago and before that we were thin.
Basically and white food is bad.
Sugar, pasta, all bread and so forth.