Speaking of weight loss. We will naturally burn about a pound to a pound and a half a day just being alive. If you eat zero calories your body will burn a pound or so just staying going. Another thing is aspiration. You will lose water weight, every breath you take you breathe out some water. This is another reason to keep hydrated, you lose it in more ways than just sweating. People can severely dehydrate themselves indoors too.
Ok you are out working in the yard, or garden and sweating like a pig, your shirt is soaked. Hmm I am sweaty, I am dehydrated I better drink some water. yes no brainer there. BUT you can be relaxed and laying in the air conditioning in the house with a ceiling fan going and that will dehydrate you almost as badly. Id say the house is worse because you don't realize it's happening because you are comfortable, but it is happening, so you need to keep drinking that water to stay healthy.
Here's some more motivation. EVERY breath, you breathe in Oxygen. that's O2, and every breath you breathe out some Carbon Dioxide, that's CO2. Where did that Carbon come from? Well we ARE carbon based life forms, so it came from US! it's a waste product of our bodies being bodies. You say you don't have the motivation to go on a diet or work out, why not? You already ARE losing weight every time you breathe out!! You are already on the right path now step it up a notch!! Every single breath you take you are losing a little bit of physical weight due to the Carbon you are exhaling. So, why not put a little bit of exertion in there and push out some more carbon and lose an extra half pound today?