So, everyone when want to lose some extra weight does what?! Starting a diet, a training, it's different diet and training from person to person.
At the end of the day or the week if the person ends up losing weight in the result of his or her training and diet consciously or unconsciously the person was in a CALORIE DEFICIT.
It means to eat less than your body needs or to workout more and burn more calories than you eat.
Now about cheating meal at the end of the week.
If you were on the diet 6 days in a week and decided to cheat the 7th, I would advise to think again and pay maximum attention how you cheat and with what you cheat.
Let's suppose that each day of this 6 you were eating or burning and creating a calorie deficit of 500 kcal a day × by 6 days you have a calorie deficit of 3000 at the end of 6 days (it's around 500-600 grams weight loss).
Now thinking that you have done well and deserve to treat yourself by a cheating meal the day 7th and for example you're cheating eating the following regular fats food meal:
Chicken nuggets 250 gr (768 kcal)
French fries 300 gr (867 kcal)
Mayonnaise 100 gr (680 kcal)
Regular cola 500 gr (250 kcal)
Ice cream 250 gr ( 540 kcal)
In reality this all grams looks very small portions, you may end up eating even more.
Now voila, if to add together the calories from your cheating meal you have about 3060 kcal in one meal.
That's all the deficit you have been on the diet the entire week, it's gone, lost for a single meal without any nutrition value after which you will be starving again and eat some another extra calories ????.
So,don't be surprised when your diet doesn't work at the end of the week