Why does caffeine give you so much energy, while being so low on calories?

Question

There's definitely something I'm missing here.Since calories is a unit of measurement for energy, and caffeine seemingly gives you a lot, how can the labels on caffeinated products have such a low calory count?I would presume that caffeine doesn't really have as much energy as it seems to give you? In which case, what does it do?Thanks in advance!

Answer 1

Caffeine may not be a primary source of the calories, but it has synergistic mechanisms to the sympathetic nervous system. Sympathetic effects cause increased cellular catabolism. Yes, it also acts on adenosine receptors and NOS on target cells, but I'm trying to keep this simple as possible. Caffeine is a phosphodiesterase inhibitor.

From the Adenylate Cyclase/cAMP Pathway, once a G protein-GTP complex activates Adenylate Cylase, ATP is cyclized into cAMP, which can then bind and activate PKA for downstream phosphorylation, activation, and biochemical/physiological effects. Phosphodiesterase can break the cyclic compound into 5'-AMP. This will basically inactivate cAMP pathway effects. By inhibiting PDE, cAMP effects are upregulated instead of downregulated.

Hence, let's say that Caffeine interacts in the cAMP pathway of epinephrine. By the mechanism just mentioned, you can see how epinephrine's effects will be upregulated. This increases sympathetic activity which increases catabolic activity like lipolysis, glycogenolysis, and glycolysis. These processes can produce ATP which can be used for cellular energy.

With regard to your question about calorie count on caffeinated beverages, it probably depends on the drink, but sodas tend to have carbohydrate like HFCS; coffee beans probably have plant carbohydrates within them; and tea may or not have sugar.

Be that as it may, because caffeine is an adrenergic angonist in its own way, the extra energy comes from increased biomolecule catabolism as a result of increased sympathetic nervous system activity.