Dietary modification is essential for treating nonalcoholic fatty liver disease (NAFLD); however, the dietary components are less well defined. We enrolled 252 adults with no history of liver disease and excessive alcohol use to evaluate the relationship between macronutrients and NAFLD and insulin resistance. Participants took photographs of their meals and documented their food intake in a food diary for seven consecutive days. A dietitian estimated the type and portion size of food items and analyzed nutrients with INMUCAL-Nutrients software. Later, participants underwent transient elastography to diagnose NAFLD and blood tests to measure insulin resistance using the homeostasis model. Total energy intake and the proportion of carbohydrate, fat, and protein consumption did not differ between participants with NAFLD (n = 41) and those without NAFLD (n = 211). Using multiple logistic regression analysis, daily intake of protein < 1.0 g/kg (OR: 3.66, 95% CI: 1.41–9.52) and full-fat dairy product ≥ 50 g (OR: 0.42, 95% CI: 0.18–0.99) were associated with NAFLD. Insulin resistance was associated with a daily intake of protein < 1.0 g/kg (OR: 3.09, 95% CI: 1.59–6.05), full-fat dairy product ≥ 50 g (OR: 0.46, 95% CI: 0.25–0.82), and dietary fiber ≥ 8 g (OR: 0.41, 95% CI: 0.22–0.74). Our data show that a low protein intake increases the odds for NAFLD and insulin resistance. Contrarily, a high intake of full-fat dairy products and dietary fiber has been associated with a potential protective effect against NAFLD and insulin resistance.