In the world of weight loss products, caffeine has become a popular ingredient as well as a regular feature in some diet regimes.
The physiological effects of interest for weight loss with caffeine are much to do with caffeine being a stimulus of the sympathetic nervous system (SNS). These SNS effects have been shown to increase both energy expenditure or in others words calorie burning, overall, potentially through triggering a general stimulus of energy metabolism, as well as potentially some energy-wasting mechanisms such as thermogenesis.
It can also be a cognitive stimulant and through interaction between the central effects of caffeine on the brain, and the locomotor system which controls your movements (aka the musculoskeletal system), may contribute to a stimulus of more spontaneous physical activity too. Another interesting action of caffeine is on fuel burning with evidence demonstrating caffeine can be a stimulus of fat oxidation, particularly during exercise, which can have beneficial effects on exercise performance.
So far, so promising, but what is the evidence that we can support for weight loss? Firstly, the magnitude of some of the physiological effects may not be as large as you may think. Studies looking at supplementation of relatively large doses of caffeine may only demonstrate fairly small changes in energy expenditure and absolute levels of fat oxidation.
These fine margins are often statistically significant but may not translate into higher measurable changes, especially given the measurement error for some parameters such as metabolic rate or thermogenesis.
Several studies have looked at the impact of caffeine supplementation on weight loss and, similarly have shown clear associations between increased caffeine intake and greater weight loss, but the magnitude of differences seen are on the boundaries of clinical significance.
Part of the problem is also pinpointing the direct effects of caffeine itself rather than other associated changes, like diet and lifestyle, that may also happen because of enrolling in a trial. This is further confounded by the differences in responses to the dose of caffeine given between people. For example, habitual caffeine consumers have less effect from supplementation than those of low caffeine intake
So, put all together, caffeine mechanistically and statistically can show effects that are beneficial to weight loss, hence their inclusion in weight loss products and supplements, but the magnitude of their effect is often not enough to herald them as the magic ingredient.
Despite caffeine’s effect on weight loss remaining somewhat inconclusive, its effect on training performance is undisputed. It’s because of this that we include the nootropic as a key ingredient in our Boost supplement, along with the calming amino acid, l-theanine, for a well-studied, synergistic combination that gives you a clear, calming energy boost.