Body shaming trolls are alive and well on social media site Instagram. But this time it's not such a clear cut case of trolling. Model Katherine Webb was forced to defend her slender physique against online critics just after posting a stunning bikini shot on Instagram this week. Former beauty queen-turned-model Katherine Webb has hit back at critics who have claimed that she is 'too thin', saying that her slender figure is a result of her overactive thyroid, rather than being a sign that she is struggling with any weight loss issues. Just hours after posting a stunning shot of herself modeling a bikini onto her Instagram account, the 25-year-old former Miss Alabama winner lashed out at those who suggested she is too thin and needs to put on weight. 'To all of you who think I need to gain weight or eat more, I eat just fine,' she commented, after sharing some of the more hateful comments that had been made under her bikini picture. 'I am 5'11 so I have a lot more places to put my calories. I eat c**p most of the time anyways. And to all the middle-aged women who like to leave mean comments on my page about my body, you can gladly skip my page and go somewhere else. 'I am tall, I eat just fine and also suffer from thyroid problems so don't make fun of me or my body when you probably have problems of your own. I rarely react to this kind of stuff, but this really bothers me.' Katherine's outburst came after she shared an image of herself wearing a skimpy black bikini on her account on Tuesday evening, telling fans that she was 'getting ready for swimsuit season on the West Coast'. Within minutes of publishing the image, the model found herself on the receiving end of a series of hateful comments, with many people suggesting that she was too thin and needed to gain some weight. 'Have a donut, make that a dozen,' one person wrote under the image, while another added: 'Love you but please gain a little weight.' Others suggested that the model, who is known for being a rather regular selfie taker, has recently shed a few pounds, noting that she looks a great deal thinner in this particular image than in any of her other bikini shots. 'Someone please give her a sandwich,' one user said. 'What happened she looked amazing, but now is looking anorexic.' Indeed, upon comparing this image with another of her bikini-clad selfies, taken seven months ago, it does seem as though the model has slimmed down slightly. But this is not the first time that Katherine, who married her longtime boyfriend, NFL quarterback AJ McCarron in July last year, has been criticized about her weight. In May 2013, the model came under fire from health experts after admitting that she was following a strictly-controlled 1,120-calorie diet - consuming 600 calories less than the daily recommended intake. If you are following a 1,200 calorie a day diet - should you be promoting Carl's Jr. Burgers / Fast Food that likely packs more calories in one meal than the entire daily calorie intake you allow yourself? If you are a role model and wield influence what exactly does this communicate? I starve myself but get paid for promoting the consumption of fast food? The hypocrisy is astounding. Katherine, who at the time was preparing for her debut Sports Illustrated shoot, told People magazine that her average daily diet consisted of a homemade smoothie for breakfast, a green apple for a snack, a spinach salad with almonds and strawberries for lunch, a frozen yogurt bar as her second snack and grilled chicken fingers with sweet potato fries for dinner. She added that, whenever she had a big shoot or event to prepare for, she 'cut out any type of bread product, and cake, cookies, bagels'. What are your thoughts on this controversy?