Combined effects of red pepper and caffeine consumption on 24 h energy balance in subjects given free access to foods

The effects of red pepper and caffeine ingestion on energy and macronutrien t balances were examined in eight Caucasian male subjects. All subjects par ticipated in two randomly assigned conditions: control and experimental (re d pepper and caffeine). After ingesting a standardized breakfast, subjects ate three meals ad libitum (lunch, dinner and breakfast) and snacks which w ere served approximately 2 h after the lunch and dinner over a 24 h period. Two appetizers (2 x 322 kJ with or without 3 g red pepper) were given befo re lunch and dinner, and a drink (decaffeinated coffee with or without 200 mg caffeine) was served at all meals and snacks except for the after-dinner snack. It is also important to note that on the experimental day, 8.6 and 7.2 g red pepper were also added to lunch and dinner respectively. Red pepp er and caffeine consumption significantly reduced the cumulative ad libitum energy intake and increased energy expenditure. The mean difference in ene rgy balance between both conditions was 4000 kJ/d. Moreover, the power spec tral analysis of heart rate suggested that this effect of red pepper was as sociated with an increase in sympathetic:parasympathetic nervous system act ivity ratio. These results indicate that the consumption of red pepper and caffeine can induce a considerable change in energy balance when individual s are given free access to foods.