Freelee was also critical of Emma's appearance, advising her to stop eating so much almond butter to "sort out her skin" and claiming the teen was "quite affected under the eyes" because of her coffee consumption and sleep pattern.
"The darkness under her eyes is definitely a sign that she is not getting enough sleep," Freelee said.
"She seems sick to me and this is sad … I am worried about Emma Chamberlain because she seems to be going downhill."
Freelee ended the video by warning that Emma could be "in rehab before you know it" if she continues to get wrapped up in the "LA lifestyle".
The vegan star's critique of Emma didn't go down well in the video's comment section where she was criticised for being unfairly harsh on the teen.
"This is madness! Praising her for not wearing any makeup then proceeding to bag her for having dark circles under her eyes," one commenter said.
"I love how you watched all of 3 videos and are speaking like you've been her doctor for the last 18 years," said another.
"This video was offensive from beginning to end," fired another.
In another video, Freelee was again critical of Emma, this time taking aim at her vlog about a healthy meal she had made, blasting her for using "junk food" cauliflower chips that were "full of fat".
Freelee ended the video by urging Emma to go fully vegan and "realise your potential".
"Leave the animals alone, leave the cows alone because you're obviously a kind person, you're obviously a cool chick, makeup free and everything," she said.
"But if you continue to hurt animals through your diet and promote to viewers you are really falling short of who you are deep down and your potential."
Freelee first made headlines in 2014 after revealing her extreme diet, which includes being "raw until four" — aka eating no cooked or warm foods until the afternoon.
She eats "mono meals" that involve just one fruit in a large portion, such as two entire pineapples in a sitting or five mangoes, two litres of orange juice or as many as 20 bananas at a time.
In the afternoon her "mono meal" can involve eating several kilograms of baked potatoes.
Since moving to South America, Freelee leads an off-the-grid lifestyle that involves her spending "most of my day nude", showering in "monsoonal rains" and eating "organic fruits and vegetables picked from the land".
