Obese children are less likely to complete school than their peers of normal weight and also had body image problems, according to an European research.
And these problems are likely to become bigger and bigger as the waistlines of European children expand - led by Ireland with 27.5 percent of under-fives classified as overweight, according to findings presented at a European Congress on Obesity in Prague, Czech Republic.
Britain had the second-highest rate with 23.1 percent, followed by Albania with 22 percent and Georgia with 20 percent, Bulgaria with 19.8 percent and Spain with 18.4 percent, said an analysis of data provided by 32 countries in the World Health Organization's 53-member Europe region.
Kazakhstan had the lowest rate at 0.6 percent, Lithuania 5.1 percent, conference host the Czech Republic 5.5 percent, and Tajikistan six percent.
People are classified overweight if they have a BMI (body weight index, a ratio of weight to height) of 25 and higher, and obese from a BMI of 30.
A second study presented at the congress said only 56 percent of children in Sweden who had received treatment for obesity completed 12 years or more of school, compared to 76 percent of normal-weight peers.
Differences in gender, ethnicity or socioeconomic status did not affect the result, said the research conducted among nearly 9,000 youngsters in Sweden.
The reasons were not clear, but study author Emilia Hagman of the Karolinska Institutet theorized that bullying might be a factor.
"If you are being bullied at school, you are feeling all this stigmatization, you don't really want to go to school so maybe school absences could be one reason," said Hagman.
"Maybe you don't sleep well at night so how easy is it going to be to sit in the classroom the day afterwards and learn? There are many, many reasons."
A third research paper, conducted in England, found that children as young as six can be dissatisfied with being overweight.
Data was collected from 301 pupils from six years of age from eight primary schools in Leeds.
Of the group, 19 percent (59) were overweight or obese and had "higher body shape dissatisfaction scores on average than normal weight children," said a statement.
Girls had a higher dissatisfaction score than boys showing they had a greater desire to be thin even at this young age, according to the authors.
"Obesity prevention programs need to consider psychological well-being and ensure that it is not compromised," said researcher Pinki Sahota of the Leeds Beckett University.
According to World Health Organization, 42 million children under five were overweight or obese in 2013.
Obese children experience breathing difficulties, bone breaks, high blood pressure and "psychological harm", according to a WHO Factsheet.
Childhood obesity has been associated with a higher risk of obesity, premature death and disability in adulthood.