How It Affects Performance
Caffeine ingestion provides performance benefits because of anti-fatiguing effects. A 2015 study found that acute caffeine intake before training increased the number of reps performed doing bench press by 11%. As the. body burns through energy stores throughout the day, the brain increases the production of adenosine to slow you down and give the body a chance to recover. Caffeine blocks adenosine receptors in the brain, making you feel more alert and focused. Most research on caffeine and performance uses relatively high doses for quicker results as caffeine is absorbed into the body at a high speed however, smaller doses work too. A recent study found performance benefits of caffeine with a caffeine intake of 1.5mg per kg of bodyweight. Your caffeine tolerance will have an influence of how well caffeine intake before training affects performance; for example, if you are a regular coffee consumer, your body may not react as much in terms of better performance.
Most importantly, take sleep into consideration. It is recommended not to consume caffeine supplements such as coffee at least six hours before bed. If you are someone who prefers to train later in the day, it is generally best to leave out caffeine supplements such as pre-workout. If you do choose to use pre-workout to complement your training, do take into consideration that most brands contain high levels of sugar to give a sugar rush alongside the caffeine boost and the sugar content should be considered in terms of the negative contribution towards nutrition.
For someone trying to reduce the number of calories in their daily intake, caffeine is an effective tool for helping feel fuller for longer, however this should not be abused.