Your gut does not just process the food you eat. Recent studies have shown multiple other functions.
Most studies have evaluated the role of bacteria in the gut, and probiotics have taken the nutrition industry by storm. We have published a number of articles on the topic , particularly on the relationship of gut flora and the immune system, including immune diseases such as Multiple Sclerosis.
Don’t think about your gut as a passive organ: It contains the Enteric Nervous System. Quoting :
“…[the Enteric nervous system] controls motor functions, local blood flow, mucosal transport and secretions, and modulates immune and endocrine functions…”
Now this enteric nervous system has been shown to even food analysis capabilities. These receptors analyze ‘taste’ the gut content and transmit signals that regulate nutrient and their uptake, and also the release of gut hormones and neurotransmitters involved in the regulation of energy and glucose.
More specifically: caloric intake, pancreatic insulin secretion, and metabolism, detection of ingested harmful drugs and toxins 
Obviously the “tasting” results are not communicated to same parts of the brain as the tasting results from the tongue!
Why is it so important? Well, it is not enough to present food to the digestive system, the research implies that the gut will to an extent, selectively process what is presented. This adds another reasons that the same food ingested by different people could have different nutritional effects, and is another factor in metabolic differences between individuals.
More precisely,the gut regulates energy (caloric) absorption, pancreatic insulin secretion. In addition, molecular sensing in the GI tract can also detect ingested harmful drugs and toxins. 
This has potent implication in the treatment and prevention of obesityGastrointestinal targets to modulate satiety and food intake. and diabetes Type II.
The gut sends out satiety hormones which itself promotes the secretion of enteroendocrine cells controlling the appetite. We are talking about a potential novel treatment of obesity! 
Anatomy and physiology of the enteric nervous system; Gut 2000;47:iv15-iv19 doi:10.1136/gut.47.suppl_4.iv15
Taste receptors of the gut: emerging roles in health and disease. ; Gut. 2014 JanAm J Physiol Gastrointest Liver Physiol, 2006 May 18
“Taste receptors in the gastrointestinal tract. I. Bitter taste receptors and alpha-gustducin in the mammalian gut.” ; 2006 Aug;29
Gastrointestinal targets to modulate satiety and food intake. ; Obes Rev. ; 2011 Jun