[300-500 kcal's generally touted for muscle preservation for those not on steroids by the internet, but that's still pretty slow and not obvious weightloss against a backdrop of fluctuating water weight]

It is obvious if you weigh yourself every day for a couple months or longer and you know how to do stats.

(FWIW, my weight since 12 February fits to a straight line a + bx where a = (93.74 ± 0.19) kg, b = (−0.018 ± 0.007) kg/day, and x is the time elapsed since 12 February; the RMS of residuals is 0.68 kg. Approximating the posterior pdf of b as a Gaussian, which ought to be close enough given 46 degrees of freedom, I'm 99.42% sure that b < 0.)