these substances have been the subject of much research and debate. personally I think they are just signaling molecules to give the central nervous system (brain) and idea of your nutrtional status. the brain decides what to do with the message it is given. depending on your genetics, enviroment, lifestyle the brain determins what to make of the signals given.
if your malnorished in some way that affects how the brain decides to respond to leptin and insulin. it may decide to slow your metabolism down, it may decide based on its programming, if I may use that term, to increase your fat mass and decrease muscle mass, it may decide to make you sluggish and lazy it may increase your appetite and desire for lots of simple easy to process calories like sugar and easy digestable carbs. it may manifest as obesity which in my mind is the last ditch effort of the body to deal with chronic nutrtional deficiencies. diabetes, heart disease, cancer, chronic infections are just the result of losing the battle due to these deficiencies.
while people demonize people who are obese as if they did it on purpose and are just lazy, dumb, or unmotivated, I cannot imagine that millions of people are actually moral deficient in this area, tho they might be in other areas, because being obese is not fun at all. sure fornication is fun, or lying to get off work or stealing something you want and getting away with it is fun which is why people persist in it and do it on purpose, obesity is not fun and is not done on purpose.
I have to put part of the blame on the news media, the corporations that deal in diets, the medical experts, the social experts etc for this prejudice and hatred of fat people. the other part in on people (sure I have been guilty of this also) believing every thing they hear just because some “expert” says something is true.
leptin and insulin have interesting functions, they are still learning, but basically the most important function of insulin is as a break rather than a exitatory function, for example sugar will eventually get into your cells (if your cells are receptive or healthy) without insulin but it is a bit slower, the high sugar is not caused by the sugar you ate but by the liver pumping out vast amounts, sure insulin speeds up uptake of sugar, but without insulin the liver pumps out excessive amounts and cause a temporary high sugar, insulin is a break on gluconeogensis by the liver. a basal amounts of insulin says to the liver hold on there no need for sugar yet.
so if your insulin resistance it is as if your a diabetic type one as far as your liver is concerned. it stops responding and keeps pumping out sugar. so as a result the body pumps out more insulin to shut the mechnism down, which is where the hyperinsulinemia comes from, eventually the liver shuts off, (and thus your not full diabetic yet) but then the sugar levels fall rather rapidly (esp at night) and thus you get hypoglycemia symptoms even tho sugar levels are normal per lab results. but your brain detects the fall and interprets it as low blood sugar (consider higher sugar is required to overcome the cellular resistance to glucoe uptake as well)
leptin is also high if your insulin levels are high, insulin triggors the leptin release by fat cells as nutrients are taken up. fat cells re last to become resistant to glucose uptake and insulin. that is why fat cells pump out lots of fat while insulin and sugar are still somewhat high becaue the cells unable to use glucose very well are to dependant on fat to survive so fat cells keep pumping it despite the insulin presence in high amounts. fat cells are ignoring the insulins break on fat release.
thus it is the central nervous system that decides whether the body is going to respond normally to insulin and leptin not the substances themselves. hence correct the messages given to the brain (aka heal the breakdown in the cells membrans and internal structures that cause the glucose intolerance,) and the brain will also heal and change it’s commands to the body.
more about this at a later date. I want to look up the link and put it in another post.