Sperg ahead
She's lost almost 15lbs in 5 days so 3 lbs a day. 1lb of fat loss is equivalent to 3500 calories. To lose 3lbs per day she would need a calorie deficit of 10,500 per day. To give her the benefit of the doubt let's say 1/3 or 2/3 of her weightloss is water weight. So 10lbs of fat loss in 5 days she would need a deficit of 7000 calories per day. And 5lbs of fat loss in 5 days she would need a 3500 calorie deficit per day.
Her bmr is 2100. If she did fuck all the entire day she burns 2100 just existing. If she ate nothing she would still need to burn an extra 1400 calories per day for 5lbs fat loss over 5 days, 4900 per day for 10lb loss and 8400 for 15lbs. Waddling around the house and rolling down hills don't burn those kind of numbers.
It's also strange to have consistent water weight loss for 5 days. If she had altered her diet and lessened her salt intake that retained water would be released in a couple of days. But she's still eating high sodium foods such as a family sized bags of chips.
Dr now's gives his 600lbers a 1200 calorie diet with the goal of losing 30lbs in 1 munt. You're telling me Chantal who is half the size of those 600lbers can do that in just 10 days if she keeps going at this rate

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The math just isn't mathing. My money is on drugs.