Washington D.C. [USA], Nov.28 : Its not unknown to anyone that Blac Chyna has always been a huge motivation in fiance Rob Kardashian's weight loss journey.

But according to a source, she is going all wrong about it as Chyna apparently thinks 'taunting' Rob is going to work, reports HollywoodLife.com.

Speaking to the webloid, the source told, "Between breastfeeding and doing some light exercise, dropping weight is so easy for [Blac Chyna]," adding, "But Rob has to go on an extreme diet and exercise nonstop and only then will he lose maybe a pound or two a week. Meanwhile Blac isn't making it any easier on him, teasing him about how much more weight she's lost. Blac thinks taunting him is good motivation but so far it isn't working."

After spending years in recluse, wracked by anxiety, depression and agoraphobia, Rob gained a significant amount of weight, and was diagnosed with Type 2 diabetes, as well.

Hence, the Kardashian brother has been trying his hardest to stay on the straight and narrow when it comes to his health and fitness. (ANI)