The EAT trial was comprised of the early introduction group, which continued to breastfeed while six allergenic foods were introduced, and the standard introduction group, which were instructed to exclusively breastfeed to around age 6 months and consumed no food in that period, according to British infant feeding guidelines.
Gideon Lack, who is a professor at King's College from London said that the outcome of this study showed that giving solid foods to babies really helps them sleep better.
The babies who ate solid foods during the study, slept about 17 minutes longer, which can mean up to two extra hours of sleep per week.
Lack said a crucial finding is that parents who were asked to exclusively breastfeed had nearly twice the odds of reporting a serious problem with their child's sleep than those who were asked to introduce their babies to solid food early.
However he also stated that he believed "the most likely explanation for our findings of improved sleep is that that these babies are less hungry".
Child food experts at University College London advised parents to choose bitter vegetables such as broccoli, spinach or cauliflower as their baby's first solid food. Infants who started solids early also woke up about 9% less often.
It comes after a milestone study by Professor Lack's team two years ago found allergies are actually less likely if certain foods - particularly peanut butter - are given to babies from an early life.
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The new data come from the EAT study, which involved 1,303 infants and was created to investigate whether introducing solid foods earlier might help prevent food allergies.
While the practice did not provide for totally uninterrupted nights of sleep, the study of 1,303 children in England and Wales between 2009 and 2012 showed that babies given solids earlier than now recommended did improve their sleep patterns.
Michael Perkin, of the Population Health Research Institute and St George's Hospital, both in London, said results from the new analysis suggest that better sleep could be another benefit of starting solids early.
Officials, however, insisted mothers should continue to follow the current advice until new guidance is published.
'We are encouraging all women to stick to existing advice to exclusively breastfeed for around the first six months of age.
"We expect to see updated recommendations on infant feeding in the not too distant future". If there is any doubt about what's best for your baby, please seek advice from your doctor or health professional'.