What is more important or does it not matter? Weekly calorie intake versus daily intake? I am asking because my maintenence level (BMR multiplied by 1.4) minus 500 calories is: 2178 calories per day. Sometimes I go way below that level and end up with 1750-1800 calories for the day and other days I might be a bit above it with 2200-2350 calories. Should I focus on the week's total caloric intake or be more focused on the individual day? Ive also read that varying your calorie intake helps keep your body and metabolism from adjusting. Today is going to be one of those days a bit above my diet level.

My nutritionist insist it's more about a weekly picture then daily, or even monthly. If you eat a bit too much, it's stored in fat. If you eat a bit too little, it's taken from fat....so long as you don't go crazy (like only 200 calories or 7,000 calories) it should be fine.

Some would even argue that mixing it up is good; give your body a bit more then it needs every now & then. I recall one diet that actually prescribes you give your body 2-3 days of excess....they claim it tells the body food is plentiful and it lets your body burn rich, THEN you do 5 days of lean an it supposedly maintains the rich-burn but takes it all from fat. I'm sure it's just a fad-diet, but still....food for thought.

I think of it like a long bike ride where you finish atop a peak....some sections go up, some are level, some even go down a bit....but overall, in the grand scheme of things, the final result winds-up at the peak. Your course may not always been straight dieting, but that doesn't mean you can't get where you wanna go.

Yup, what BSL says. Your weekly average is most important. You want to try not to go too low, but some days that's just inevitable. I know yesterday I left almost 1000 calories on the table after a long bike ride and a run. I tend to eat (and have in the house) low fat, low calorie, high nutrient food and the ride was later in the day, the run finished at 7 p.m. and I just didn't have the food in the house to eat appropriately. So today breakfast was larger than normal, lunch was pretty filling, and I didn't get up to swim. (Okay maybe that's just because I had an ephiphany that it was spring break and my triathlon isn't until August so ONE day of sleeping in won't kill me.)

In fact my nutritionist suggested I eat about the same calories every day, estimating it based on what my average training week is. I still LIKE eating more on heavy training days so I plan for that, but my average intake stays around 1400-1500 over the week per day net (calories in-calories out) and about 2300 per day gross for 120 lb woman.

It's the average of any given time based on your energy needs for that time frame.

So per hourly, you should average so-so. Per day, you should average so-so. Per week, you should average so-so. Per month, you should average so-so. Per year, you should average so-so. Per decade, you should average so-so. Per life time, you should average so-so. The "so-so" average should match your required intake depending on your activity level. So on given period of time you do the most activity, your average "so-so" should be high; where as periods of lesser activities, your average "so-so" should be lower.