The topic of thinning fruit trees is probably involved with the statement, 'The fruit is too heavy for my tree branches',  because of heavy fruit on sagging or broken branches. Assuming that the fruit tree in question is properly pruned, the sagging branches are indicative of too much fruit ( or weight ) for the girth of the branches.

There are two avenues to pursue to alleviate the problem. The first suggestion would be to brace the branches with supports to prop them up. The second method is fruit thinning. Thinning means physically removing some flowers along each branch or removing the small fruit so as to create a 6 inch space between each fruit. If the grower wants larger amounts of small fruit, do not thin extensively, and then apply the supports for the branches. If the grower prefers larger fruits, thin to allow for 6 inches between fruits.

Another suggestion for heavy bearing fruit trees is to remove the fruit from the end of each branch. Remove the fruit from at least 12 inches from the end of each branch. The tree branches will then have a much higher likelihood of supporting the weight of the rest of the fruit without much support or no support at all.