The participant was in floods of tears after the dressing down on the RTE show.
Later, the Montrose station was inundated with phone calls and emails about the outburst and users went online to describe Dr Eva's reaction as "an utter disgrace".
The nutritionist was busy working with clients in her practice -- Orsmond Clinic -- all day yesterday. Staff told the Herald that she was running a "double clinic" and was unavailable for further comment.
On Wednesday night's show the doctor, who runs nutrition clinics in Dublin, Kildare, Limerick, Galway and Kilkenny, defended her actions on the show.
She said she was using Charlotte as an example for the tens of thousands of people who are overweight or obese in Ireland and described it as a dose of "tough love".
"Charlotte is representing around 150,000 young people out there who are either overweight or obese and I was using her as an example to try and wake up those young people who are in my opinion wasting their lives," she said.
Dr Eva dismissed criticism and said she had a "constructive" meeting with Charlotte after Wednesday night's show.
"I have good intentions in my heart," she said on the show. "I am a very caring person and I really do want the best for people. If it needs to be tough love at times then that is what you're going to get," she added.RTE has defended the doctor's actions.
"Her reaction to Charlotte's weigh-in this week may have been forceful but we felt that this was an important marker in Charlotte's journey and therefore decided that it should be part of the programme," RTE told the Herald.
"Dr Eva has been working with Charlotte in Cavan this week, they have a good relationship and we look forward to Charlotte continuing on her weight-loss journey next week with renewed energy."
One commentator labelled the behaviour as "an utter disgrace".
Another said: "After watching I think the show is reality TV and nothing else."