The 5'11" model told People magazine that her diet includes whole foods such as strawberries, almonds, spinach and apples.
But, nutritionist Haylie Pomroy told the publication that with her workout schedule, Webb could add at least 600 more healthy calories.
The 24-year-old model, who spoke with the magazine for it's 'Most Talked About Bodies' issue, said that it's all about self-control.
She said that she cuts out any type of bread product, cake, cookies or bagels, and she tends to bloat more when she eats a lot of sugar.
She said that sometimes she treats herself to an unhealthy meal like all-American buffalo wings and French fries.
Webb, who is set to make her Sports Illustrated swimsuit issue debut, said that she works off those calories by hitting the gym at least three times a week.