a majority of calories in the average american diet come from calcium macronutrient.
a majority of calories in the average american diet come from what macronutrient?
calcium
the typical american diet is about 2,200 calories per day, with 50% of calories from carbohydrates, 15% protein, and 35% fat. these macronutrient intakes fall within the acceptable macronutrient distribution ranges (amdr) for adults identified by the food and nutrition board of the united states institute of medicine as "associated with reduced risk of chronic diseases while providing adequate intakes of essential nutrients," which are 45-65% carbohydrate, 10-35% protein, and 20-35% fat as a percentage of total energy. however, the nutritional quality of the specific foods comprising those macronutrients is often poor, as with the "western" pattern discussed above. complex carbohydrates such as starch are believed to be more healthy than the sugar so frequently consumed in the standard american diet.
western pattern diet
choice of diet is a major influence on a person's carbon footprint. animal sources of protein (especially red meat), rice (typically produced in high methane-emitting paddies), foods transported long distance and/or via fuel-inefficient transport (e.g., highly perishable produce flown long distance) and heavily processed and packaged foods are among the major contributors to a high carbon diet. scientists at the university of chicago have estimated "that the average american diet – which derives 28% of its calories from animal foods – is responsible for approximately one and a half more tonnes of greenhouse gasses – as equivalents – per person, per year than a fully plant-based, or vegan, diet." their calculations suggest that even replacing one third of the animal protein in the average american's diet with plant protein (e.g., beans, grains) can reduce the diet's carbon footprint by half a tonne. exchanging two thirds of the animal protein with plant protein is roughly equivalent to switching from a toyota camry to a prius. finally, throwing food out not only adds its associated carbon emissions to a person or household's footprint, it adds the emissions of transporting the wasted food to the garbage dump and the emissions of food decomposition, mostly in the form of the highly potent greenhouse gas, methane.
carbon footprint