 Labradors like to eat , and without proper exercise can become obese . Laziness is a contribution to this . Obesity is a serious condition and can be considered the number one nutritional problem with dogs . A study shows that at least 25 % of dogs in the United States are overweight . Therefore , Labradors must be properly exercised and stimulated . A healthy Labrador can do swimming wind sprints for two hours , and should keep a very slight hourglass waist and be fit and light , rather than fat or heavy @-@ set . Obesity can exacerbate conditions such as hip dysplasia and joint problems , and can lead to secondary diseases , including diabetes . Osteoarthritis is very uncommon in older , especially overweight , Labradors . A 14 @-@ year study covering 48 dogs by food manufacturer Purina showed that Labradors fed to maintain a lean body shape outlived those fed freely by around two years , emphasising the importance of not over @-@ feeding . Labradors should be walked twice a day for at least half an hour . 
