Motivation to keep you in the gym, in shape, and eating healthy can come from lots of places. If that's not enough to get you exercising and watching your diet, then this discovery should help: The fat in obese people eventually becomes so stressed by the accumulation of weight that it becomes scarred and extremely hard to lose, according to a recent study published in the journal Metabolism.

Researchers took fat samples from obese people who had undergone bariatric surgery—a procedure that reduces the size of the stomach to help with weight loss—and compared them to the fat tissue taken from lean people who had elective surgeries. They found that the heavier people had high amounts of a molecule that creates scarring by stiffening up tissue, which makes it less able to expand, store energy, and function properly. Scarring makes the fat unable to do its job, and has been shown to lead to fatty liver disease, cardiovascular disease, and diabetes.

"Scarring of fat tissue may make weight loss more difficult," said Katarina Kos, M.D., Ph.D., senior lecturer at the University of Exeter's Medical School. "But this does not mean that scarring makes weight loss impossible. Adding some regular activity to a somewhat reduced energy intake for a longer period makes weight loss possible and helps the fat tissue to not become further overworked. We know that doing this improves our blood sugar, and is key in the management of diabetes."