Fast-Food Diets and Metabolic Response

Background and methodology 
The fast food industry provides large quantities of food for many people every day, however, little is known about how this food may impact metabolic responses compared to ‘healthy’ meals of a similar composition. This study was based on three-way crossover design. Six overweight men were given a standard breakfast at 8 a.m. on each of three occasions, followed by one of three lunch menus at noon. The menus included: (1) a fast-food meal consisting of a burger, French fries and root beer sweetened with high fructose corn syrup; (2) an organic beef meal prepared with organic foods and a root beer containing sucrose, and (3) a turkey meal consisting of a turkey sandwich and granola made with organic foods and an organic orange juice. Glucose, insulin, free fatty acids, ghrelin, leptin, triglycerides, LDL-cholesterol and HDL-cholesterol were measured at 30-minute intervals over 6 hours. Salivary cortisol was measured after lunch.

Total fat, protein and energy content were similar in all three meals, but the fatty acid content differed. The fast-food meal had more myristic, palmitic, stearic and trans fatty acids than the other two menus. The pattern of nutrient and hormonal response was similar for a given subject to each of the three meals. The only statistically significant acute difference observed was a decrease in the area under curve of LDL-cholesterol after the organic beef meal relative to that for the other two meals. Other metabolic responses were not different. LDL-cholesterol decreased more with the organic beef meal, which had lesser amounts of saturated and trans fatty acids than in the fast-food beef meal.


Bray, G. A., Most, M., Rood, J., Redmann, S., and Smith, S. R. (2007). Hormonal responses to a fast-food meal compared with nutritionally comparable meals of different composition.  Annals of Nutrition and Metabolism, 51(2), 163-171.