Niomi has probably under eaten for so many years that her body has adapted to the lower calories. Even in that old photo of her you can see she has very little muscle tone. The only way a person can have lean muscle tone is to grow lean muscle. You grow muscle by eating in a small excess and eating decent amounts of Protein. She obviously isn’t eating enough protein OR general food because if she was, with the amount of exercise she claims she does, she would actually have a very lean and toned body. Same with Tanya’s weight loss. She has no muscle, which means she probably just starved herself thin with little exercise to build muscle. Anna you can see has more muscle on her, so she either has done some exercise in the past, doesn’t drastically under eat, or is extremely lucky to have a body that naturally is more muscular.I would argue that Niomi isn't "naturally" thin. She's not like Zoe Sugg.
I think it takes a lot of deficit for her to remain thin, which is why she's so obsessive with it. Zoe doesn't need to get up off the sofa and she's as small as Niomi - Niomi has to do excessive exercise every day and undereat.
With the amount of info out there, people are wising up to what healthily is and looks like. Niomi won’t be able to claim she is a wellness influencer much longer if she keeps going this way. Or brands that just mascarade as ‘wellness’ we be the only ones that partner with her.