It is not controversial to state that the practice of calorie restriction slows aging - the evidence is overwhelming, and the most important remaining open questions relate to the degree to which it slows aging in humans, and how that effect manifests in health in later life. Are you practicing calorie restriction? It is certainly something you should look into - or at least discuss with your physician.
That said, there are still a near endless series of explorations that might take place into the biology of aging and how it changes with calorie restriction. The greater the capabilities of modern biotechnology, the more that opportunities open up for further and deeper detailed examination of the way in which humans work, and the way in which we change over time. The complexity of any given system in our biology is staggering - which is one of the reasons why we should pay more attention to research strategies like SENS, which explicitly seek to work around this complexity and achieve meaningful results in healthy life extension more quickly than would otherwise be the case.
Calorie restriction slows aging in most species tested to date, so we should expect to see more or less any arbitrarily picked set of changes in biology slowed by calorie restriction in those species. Here is an example from the kidney:
Chronic kidney disease and end-stage renal disease are major causes of morbidity and mortality that are seen far more commonly in the aged population. Interestingly, kidney function declines during aging even in the absence of underlying renal disease. Declining renal function has been associated with age-related cellular damage and dysfunction with reports of increased levels of apoptosis, necrosis, and inflammation in the aged kidney. Bioactive sphingolipids have been shown to regulate these same cellular processes, and have also been suggested to play a role in aging and cellular senescence.
We hypothesized that alterations in kidney sphingolipids play a role in the declining kidney function that occurs during aging. ... Importantly, caloric restriction, previously shown to prevent the declining kidney function seen in aging, inhibits accumulation of [two sphingolipids examined in this study] and prevents the age-associated elevation of enzymes involved in their synthesis.
Aging is, in the broadest sense, the accumulation of damage to our cells and the molecular machinery that lies within. Calorie restriction appears, at the very least, to enhance cellular repair mechanisms - one of the strongest indications for this to be the case is the work showing that calorie restriction stops working if the most important of those mechanisms is disabled. More repair means less accumulated damage, and thus a longer life expectancy. That, at least, appears to be the easily stated high level effect of a very complex and as yet not fully understood set of evolved metabolic processes present in most species - all of which are set in motion by the simple planned action of eating less while still obtaining optimal nutrition.
No medical technology can do as much for the healthy as calorie restriction. Which is a depressing state of affairs when you stop to think about it: we stand in the midst of a revolution in biotechnology, and as yet we don't have rejuvenation medicine. A great deal of work remains to be accomplished, for all that we can clearly see the road ahead, and describe in detail the technologies capable of reversing the effects of aging.