Hey Nic & all, I have been meaning to post a reply for a few days now, but haven't had the time to be able to put a response down without feeling like I missed stuff out, but now I have a few hours...so here goes
Before I start, Becky & NB, I hope it doesn't seem like I am trying to debunk anything you say, but if it does I am sorry, I am basically just tapping into what we have been taught throughout our course, which is generally what is accepted at the moment, but doesn't really get fed through to the public until it has been made obsolete by another study etc...but enough of that, I will get to it...
As said earlier, depending on your goal, there are different types and styles of training that are better suited to the different goals you may have.
As far as weight loss (fat loss) goes, probably the biggest factor (apart from diet - which has been mentioned but I will get to that) is the intenisty in which you train at. Because our bodies are just dandy, it takes a lot more time and effort to metabolise fat for energy (as opposed to carbohydrates - CHO), and as such the higher an intensity you train at, the greater preference the muscles have to use CHO as a fuel source, rather than fat, which you are looking to 'burn'. As such, to train for fat loss, you need to be training at not too much over 70% of your max HR (220-age is the simplistic equation, which is fine for now, but there are other equations which predict it better), or else your muscles will be requiring fuel too fast for fat to completely keep up with, so CHO will be used instead.
HOWEVER, if you are training to increase your strength/power or just general fitness, you need to be training at between 70-85% intensity (for aerobic fitness), or 85-100% for strength or power (strength/power intensity is usually measured in the % of your 1 Rep Max, or the maximum amount you can lift in one maximal effort). Again the type of training (intensity, reps etc) will depend on what your goals are - for example, in a weight training program:
- For increases in strength, you should be looking at <10 rep sets, at >85% 1RM, and 1-3 sets on each muscle group
- For purely muscular hypertrophy (and not as big an increase in strength), 6-20 rep sets @ 70-85% 1RM, 2-3 sets, and
- For muscular endurance >20 rep sets @ <70% 1RM, and around 3 sets.
This is just an example to show the differences in just one type of training, and when you combine this with cardio work, flexibility and power training, and the different types of those, it is easy to see why there is a lot of confusion, and also why a lot of people are discouraged and drop out of fitness programs, simply because their program might not be the right fit for them.
Another problem with a lot of gym-based fitness programs, as well as those at a lot of sporting clubs, is one simple thing, which is that there is generally no consideration for the "drop" part of, for example, a bench press. This portion is called an eccentric contraction, with the "up" part called a concentric contraction. In simple terms, if the muscle is only made to work in the "up" portion of a bench press, and on the way down it is simply left to gravity, there will only be a certain amount of gain in strength and hypertrophy, however if work is done on the way down (ie bringing the bar down slower than gravity), there will be a greater increase in strength as a result, mainly because it is working the muscle in a different way, and as such working it harder...
I have gone waaay off track here, so sorry, I will try and get back on...
As far as diet goes, the 3 factors are CHO, Fat and Protein
CHO - is the fuel for muscular activity - you MUST have adequate stores and intake of this, or else you will get that 'tired and lethargic' feeling, and will be unable to exercise above a certain intensity due to not having CHO available. Now having said what I said before, with fat being the main source of energy under 70% HR max, you would think that if you didn't consume adequate CHO (ie low carb diets) the body would just use fat instead for lower intensity exercise. WRONG! As NBG said earlier, if you have an inadequate CHO intake, the body will lock away fat stores and use protein as a fuel source instead, and slow the body's metabolic rate down, therefore losing muscle, and increasing fat stores due to any fat ingested being stored for "famine usage"
So basically, you should have about 55-70% of the energy you intake from food as CHO, which is normally about 5-7g of CHO/kg of body weight/day. ie, for an 80kg person, you should be aiming to consume between 400-550g of CHO/day - which means nothing at this point, however look at it this way - 50g of CHO is equivalent to either of:
4 slices of bread
2 crumpets
1 1/2 cups of cooked rice
600mL of Orange Juice
3 Large apples
2 tbsp of honey/jam
2 cups of coco pops
So, an example day - for breakfast if you have 2 slices of toast with jam, a bowl of coco pops, 600mL of OJ, for lunch you have a couple of sandwiches with honey, and for tea you have a main dish with rice on the side, there is already about 325g of CHO, without including snacks during the day...and once again I am off track...bugger...
Basically the gist is:
- You need enough CHO intake to supply the energy you are outputting each day,
- You should aim to limit fat intake to under 30% of your total daily energy, and try to aim for unsaturated fats as opposed to saturated
- And, protein intake should be about 0.8-1g/kg of body weight per day, and in training this should increase to around 1-1.4g/kg to ensure there is enough protein to allow for muscle to build and repair) - 500mL of skim milk is around 16g of protein, and 2 egg whites is around 12g, just as a couple of examples...
So far off track - read the next response for the ACTUAL training advice...sorry :S