Can nightshades cause weight gain?
The answer to this question is a bit more nuanced than a simple yes or no. Nightshades can cause an inflammatory response in some people which can cause weight gain as well as reducing one’s ability to lose weight. If eating nightshades is causing pain, then there is a chance that they’re also affecting your weight. The other way that they can affect your weight is by affecting the body’s regulation of the hormone ghrelin.
What is ghrelin?
Ghrelin is a hormone produced by cells of the gastrointestinal tract and is often referred to as a “hunger hormone” because it increases appetite. Ghrelin blood levels are highest when hungry and lower after eating. It is mostly found circulating in the stomach and in smaller amounts in the intestine. Another significant source of ghrelin is the hypothalamus, with smaller amounts produced in the placenta, kidney, and pituitary gland.
How is ghrelin affected by nightshades?
Ghrelin is a hormone that is controlled by the BCHE gene, the same gene that controls the breakdown cholinesterase which helps to regulate ghrelin levels. People with certain mutations within the BCHE gene cannot break down the cholinesterase inhibitors found in the nightshade family which means that ingesting nightshade foods lowers serum cholinesterase levels, in turn causing dysregulation of ghrelin. Studies have shown that BCHE strongly affects fat metabolism and accumulation in mice which may also be true in humans.
Source:
Chen, V. P., Gao, Y., Geng, L., Stout, M. B., Jensen, M. D., & Brimijoin, S. (2016). Butyrylcholinesterase Deficiency Promotes Adipose Tissue Growth and Hepatic Lipid Accumulation in Male Mice on High-Fat Diet. Endocrinology, 157(8), 3086–3095. https://doi.org/10.1210/en.2016-1166