This clip says good things about how stress lowers digestive function. One precise way that this happens is that when we are happy and relaxed, the stomach is lined with mucus and bicarb – otherwise it would digest itself. As a response to stress, this mucosal lining and bicarb levels are drastically reduced so when we come to eat the body simply can’t produce the necessary levels of HCl.
A simple explanation as to why stress can make us fat. In the immediate stress response, a hormone is released that actually suppresses appetite. We hardly want to start noshing on the Hob Nobs if the boss is on the rant. This hormone subsides quite quickly and other hormones are released, one of which is cortisol. Cortisol in particular hangs around for some hours after the stressful event. In the immediate ranting match it arms the body with quick energy to either thump the boss or run away.
When things have calmed down a bit, cortisol now makes the body hungry – in the assumption that, being still alive, there has just been a burst of great activity. And that hunger is specifically for carbs and fat – that packet of Hob Nobs fits the bill nicely here. A stick of celery comes nowhere and we are hardly in a fit state to digest a steak. Carbohydrate drives up blood sugar which releases insulin, a rebuilding hormone that also cues the fat cells to store fat. Eating carbohydrate along with fat ensures that the fat cells are stuffed with fat to provide a good energy store for the next stressful event – which might be spilling a cup of tea all over the keyboard followed an appalling commute home only to discover when you get there that the boiler has broken down.
The body preferentially stores this layer of fat on the abdomen ready for quick release- ready to jump up and down on that unopenable packet of ham. And, without going into detail here, an effect of repeated stress is to lower metabolic rate so we need to eat less to stay the same weight.