Pay Attention To Calories

Counting calories is a good thing, and it's something that you have to pay attention to. 
Your body will let you eat far more than is good for you, so your brain is going to have to take over managing the process.
Almost everything you buy from the grocery or supermarket has the calorie content listed on the packet. Note that most manufacturers list calorie content by portion, and that even a lowly bar of chocolate usually has two portions. Marketing departments don't like the number of calories to be too high, as people won't buy it...so they'll just divide the product into more portions with a lower calorie count per portion. Sneaky!
Most foods have more calories than you might think. You can recognize the new practitioners of calorie restriction at the supermarket: they'll be the ones looking at many different product packages and muttering "wow, I had no idea!"
For foods like apples, rice, loose vegetables and so forth, you will need a book of calorie values. Recent editions tend to contain (fairly horrifying) values for fast foods as well as the more usual suspects.
Calorie restriction (usually abbreviated to CR) is a strategy proven to extend healthy and maximum life span in rodents and primates. Some animal studies conducted over the past 20 years have shown up to a 40% increase in maximum life span - though there is good reason to believe that any gain in human life span through life-long CR would be much more modest.
Calorie restriction also provides numerous secondary benefits, such as a greatly lowered risk for most degenerative conditions of aging, and improved measures of general health. In recent years, human studies have demonstrated that these same secondary health benefits are available to you and I, not just to laboratory animals. Many researchers believe that the evidence to date shows the practice of CR will extend the healthy human life span, but a consensus has not yet been reached on this topic.

Quote:Calorie Restriction in a Nutshell
A calorie restriction diet aims to reduce your intake of calories to a level 20-40% lower 
than is typical, while still obtaining all the necessary nutrients and vitamins. CR is also 
known as CRON, for "calorie restriction with optimal nutrition," and its practitioners 
have accumulated many years of experience and experimentation. As a result, good 
books and a supportive community exist to help newcomers adopt the best practices 
for CR in humans. Mild CR may be as easy as adopting a much healthier diet, taking a 
few supplements and not eating snacks.

Modern CR Science
The beneficial effects of CR in laboratory animals have been known for a long time, 
but only in the past decade - and in particular over the past few years - has more 
funding and effort been devoted to this field. In the present day, human studies such 
as CALERIE are underway and many research groups are digging into the 
biochemistry that could explain how and why CR is so good for health and longevity.

The genes and processes that control metabolism are notoriously complex, and 
scientists do not yet have a complete understanding of the way in which CR fits into 
the overall picture. But they are working on it.

Many reputable health websites maintain an informative section on CR. Unfortunately, 
some of these resources exaggerate minor difficulties experienced by people who 
practice CR - this is something you will see in the media as well. An article from 
MSNBC in early 2003 went so far as to use the word "torturous" to describe the 
experience of trying CR! This is all far from true: starting on CR is no harder than any 
other diet change.

Weight loss should be mentioned in the context of CR, even though it is not the 
primary goal of a CR diet - if you eat fewer calories, you will slim down. Research 
indicates that being overweight, or carrying excess body fat, is harmful to your long 
term health in many different ways. Excess weight increases risk factors for 
conditions ranging from diabetes to cancer to Alzheimer's, most likely due to the 
relationship between fat cells and chronic inflammation. It is no exaggeration to say 
that if you are overweight, you will have a shorter, less healthy life - many recent 
studies suggest that even comparatively little excess weight is bad for you over the 
long term, significantly raising your chances of suffering a range of age-related 
conditions. Some portion of the health benefits of CR are likely to stem from the 
accompanying loss of weight and body fat - although biochemical research indicates 
that there is clearly more than just that going on under the hood. CR is also doing 
something positive with the controlling mechanisms of metabolism.

For example, it appears that CR provides a boost to the process of autophagy. 
Autophagy is the way in which your cells remove damaged components in order to 
recycle the materials into new replacement parts. Several lines of research indicate 
specific types of damaged cellular components left to cause problems over time 
contribute to age-related decline and damage inflicted upon the rest of your body's 
machinery. More autophagy may help reduce this contribution to the aging process