? WHEN THEY SAY

CALORIES IN VERSES CALORIES OUT. DOES THAT HAVE TO BE DONE IN THE SAME DAY OR AT THE END OF THE WEEK IN ORDER TO LOSE AND NOT GAIN.

Yes


Day to day for sure, but week to week can work too.

It just makes it easier to accommodate the old mentality of eating to much and not moving on some days and kill yourself to work it off on a couple of other days later in the week or get too much rest and defeat the effort you may have made earlier in the week.  It really depends on your health and what you are try to accompllish or training for.

The weekly totals approach will set you up to fail easier in the long term. 

Day-today, if you have a bad day or miss a work out or eat too much at a meal, it is smarter long-term to adjust the reminder of the day or worst case, get back on track the next day.  If I miss my workout in the afternoon, I try to get it in or something later in the day.  If I don't, I start over the next day, not the next week.

Do what you can, make the best of your options and cir****tances.  Thats my 2 cents. 

I usually go for a 3-4 day running average. I find one week is a bit long when it comes to energy balances.