'My 600-lb Life' Gideon of season four is one of the most complicated cases of morbid obesity that viewers have ever seen. Some details of his story are sadly commonplace. Two unusual features are that after gastric bypass surgery, the 650-lb man has no trouble with the diet, but he also sleeps all the time, even more than he did before surgery. It's derailed weight loss. What's behind Gideon's story could be more than just laziness. It might be a dangerous trifecta of depression, sleep apnea, and lack of calories.

Just a lazy, fat person?

A lot of folks assume that obese people just sit around and eat all day.

And while that is what ends up happening, as in the case of bedridden Penny Saeger, it isn't always what caused it. People usually don't begin life overweight, even though childhood obesity may have set in quickly. And lack of activity doesn't always equal lack of motivation and certainly not a desire to manipulate others. Many on "My 600-lb Life" (like Amber Rachdi) never planned to be a burden to others. There's a crippling cycle that drives obesity.

Diet and exercise don't coexist

Yes, you read that correctly. The common prescription of diet and exercise is not always possible depending on how obese you are, if you've had bariatric surgery and how much you restrict your caloric intake. Calories aren't just mortal enemies of dieters--they're a unit of energy.

Consuming calories, via food, is the only way to sustain energy. Eating fewer--especially in protein, complex carbohydrates and fatty acids--makes you lose pounds, and also energy.

Depression derails sleep, weight loss

At Gideon's size, moderate yardwork burned up to 1,000 calories, said "My 600-lb Life" Dr. Younan Nowzaradan.

And unlike other patients, diet isn't the hard part: staying awake is. Counseling uncovered some deep-seated PTSD-like depression, guilt and anxiety. All of these wreak havoc, but even they might not be the biggest problem.

Sleep apnea kills diet and more

Often, the problem behind constant tiredness is OSA or Obstructive Sleep Apnea.

This both causes and is caused by weight gain. A person of normal weight with sleep apnea doesn't get enough delta sleep. They fall asleep all the time and exercise exhausts them. They literally eat to keep awake, and put on weight. Losing weight can ease apnea but it won't erase it. Apnea is deadly and must be treated before weight loss can happen. And if you add depression and diet to apnea, it can sabotage not only weight loss, but overall health.