According to the study, the energy-draining effects of junk food can persist even when someone is switched to a healthy eating plan.
The study, conducted on two groups of female rats, found that those who ate junk food, high in sugar and low in nutrients, gained more weight than the other group who stuck to a diet of unprocessed foods like corn and fish, reports femalefirst.co.uk.
What’s more the group eating junk food also suffered from fatigue and became more sedentary and less motivated.
Researchers from the University of Los Angeles found that at the end of the six month trial they switched the rats back to a nutritious diet for nine days but it didn’t seem to affect their weight gain or laziness levels.
The result suggests that fad diets that last a week or two are going to have no real health benefit.