Response to inadequate protein in diet
I found this really interesting, thought I would share
Fat deposition in response to excess ingested carbohydrate, driven by low dietary percent protein, has been shown to be labile in laboratory selection experiments in an insect - it increased in response to habitual shortage of carbohydrate across successive generations and decreased in the face of persisting carbohydrate excess in the diet . One adaptive mechanism that helps counteract the risk of developing obesity on low percent protein diets is increased facultative diet-induced thermogenesis, whereby excess ingested carbohydrates are removed via wastage metabolic cycles, e.g. involving uncoupling proteins .
In the context of the deleterious consequences of overconsumption it is interesting to note that the major causes of increased longevity in studies on calorically restricted primates (most recently ) is a reduction in the incidence of diabetes, cancer and cardiovascular disease relative to ad libitum fed controls. This may not result from benefits associated with CR per se, but rather reflect the costs of nutrient imbalance when feeding ad libitum on a fixed diet. As the required balance of nutrients changes over time (with time of day, season, growth and development, and senescence), animals will be forced to overeat some nutrients to gain enough of others. Even if a fixed diet is nutritionally balanced when integrated across the entire lifespan (and worse if it is not), changes in requirements at a finer timescale will result in accumulated damage from short-term nutrient excesses, which may be ameliorated by modest diet restriction
When protein is eaten in higher then optimal quantities relative to non-protein energy it shortens lifespan - in insects certainly and perhaps too in mammals - but what might the underlying mechanisms be? There are several possibilities, including enhanced production of mitochondrial radical oxygen species [19,31], DNA and protein oxidative modification, changes in membrane fatty acid composition and mitochondrial metabolism [19,32], changes in the relationship between insulin/IGF and amino acid signaling pathways, including TOR [33-38], toxic effects of nitrogenous breakdown products and capacity to deal with other dietary toxins [39,40], changes in immune function to pathogen attack [41,42], and changed functioning of circadian systems . How these various components are interrelated will begin to emerge from analyses in which multiple biomarkers and response variables are mapped onto nutrient intake surfaces
If we were to propose one candidate for the hub linking nutrient balance and other inputs to longevity it would be the interplay between the TOR and AMPK signaling pathways. Both TOR and AMPK serve as nutrient sensors and are linked to nutrient intake and metabolism. Factors that directly or indirectly increase TOR signaling, including elevated nutrients such a branch chain amino acids, glucose and fatty acids, are broadly anabolic and life-shortening. In contrast low levels of nutrients, declining ATP:AMP, and other influences that stimulate AMPK signaling are catabolic and life-extending [34; 38; 44-48] (Figure 2); - except when overconsumption, obesity and insulin resistance are driven by protein shortage on a habitually low percent protein diet  (see Figure 2). Although it is not yet establish whether TOR and AMPK are nutrient balance detectors, there are suggestions that they may well be. For example, glucose activates TOR in an amino acid-dependent manner  and elevated percent protein diet stimulates TOR and inhibits AMPK (e.g. [50,51]). We predict that mapping the responses of both TOR and AMPK onto nutrient intake arrays will provide fundamental new insights not only into aging, but also a whole range of interlinked metabolic phenomena, including obesity, type 2 diabetes, cancer risk and cardiovascular disease. To illustrate this point, we have predicted response surfaces in Figure 2 and linked aspects of nutrient balance, aging and obesity within a single schema
Wow, that's the real stuff!
Can you explain it to me? Thanks in advance.
Originally Posted by piano-doctor-lady
You need some background study before this involved kind of thing makes sense. I'd recommend reading "Mastering Leptin" by Byron Richards. I had to read some of it several times before it stuck. Once you get there, abstracts like this are FUN.
+1 sorry i expect people to know what i am talking about i would say read that book though,
Originally Posted by piano-doctor-lady
Errr... at a quick skim... too much protein bad for you, probably, but too little protein plus too much carbohydrate is fattening. (Or is it saying, as an aside, that too little protein actually makes you eat more carbs?) However, if you're an insect several generations into such a diet you may have adapted to cope with the extra carbs without getting fat.
Something like that?
It's about flies! That's some serious extrapolating there.