What is the number one thing that most people will say is absolutely required for happiness in life? Health. If you don't have good health, you can't be truly happy. All of the money in the world means nothing if you are in physical pain or at risk of becoming debilitated (or dying). After health, a wide variety of other factors contribute to happiness, but clearly the needs and demands of the body come first.
A psychologist named Abraham Maslow created a pyramid which defined the needs of people. His theory was that the needs at the bottom of the pyramid formed the base, and we had to have the base needs met before we could seriously concern ourselves with needs at the next higher level. Unsurprisingly, at the bottom of the pyramid are physiological needs - food, water, sleep, etc. The things which contribute to our basic survival as organisms are first and foremost. On the next step up, is health, and on the third step, family and love. This pyramid, which is an imperfect representation of the needs of humans, is nonetheless fairly accurate for most people. We act in accordance with it most of the time, though we don't always realize it.
During one of my many failed attempts to pull my act together and lose weight, I tried to motivate myself to succeed by seeing things as a choice between my husband (who I love so dearly that it's impossible to express in mere words) and food. I visualized the choice to help motivate me by conjuring up the image of a pile of delicious food and him. This worked for a very short time, but ultimately, I was unable to sustain it. In fact, the truth was that this only made things worse as failure felt all the more crushing when I viewed it in light of this type of choice. I was not only failing myself, but him and my "weakness" was seemingly greater than the person I valued more than anything in the universe.
Women who are trying to lose weight often say they want to do it so they're around when their kids grow up. They believe they can blackmail themselves emotionally into losing weight like I once did. If they taste some success, they soon want everyone around them who also may develop or who have already developed health issues due to weight problems to lose weight also. They display varying degrees of franticness about their spouses', parent's, etc. health risks and express frustration that these people, in their estimation, value the comfort of food more than their future as a family or couple together.
They see it as a matter of the value loved ones apply to them. They think that, if this fat person who claims to love me valued me more, they'd do what it takes to lose weight. I will note that generally these sorts of assertions are made by newly minted losers in the weight loss arena. They've been on a diet bandwagon and lost about 10-20 lbs. and now they play the loudest of anyone in the group. This tiny amount of success sets off a lot of judgment of everyone around them, and they generalize the concerns that motivated them to everyone else.
If choosing to lose weight or control your eating could be effectively motivated in this fashion, there would be very few overweight people in the world. In fact, if my love and value of my husband could drive me to eat well and be healthy, I'd be the healthiest person on the planet. I value nothing more than him. My husband once said that if he had to choose between having someone shoot me or him, he's not sure he'd choose himself because he knows I'd rather die than live without him. He knows he wouldn't be doing me any favors by sacrificing himself, though he clearly would want to do so.
So, if I love and value my life with my husband so much, why couldn't I lose weight "for him"? Unfortunately, the situation is more complicated than that. The relationship we have with food is intimate, deeper, and different than the one we have with other people. It is driven internally, by both biological and psychological factors. Both of these factors are not directly affected by our love of others. When my stomach is rumbling or my blood sugar is low, my body isn't going to squelch the desire to eat in response to my love for my husband and my desire to be with him.
You can't put off a "lower need" (food) by pitting it against a "higher need" (love and belonging). The lower need will win every time as Maslow's pyramid theory illustrates. The lower needs need to be attended to first. It's not just human nature that is at play. It is survival. People have to lose weight for themselves, and it's not about a choice of food or a longer life with loved ones, though they may often feel that is so. My relationship with food came long before the one I have had with my husband, and it is integrated with me on a cellular level. Placing one relationship in a competition against the other is not only counterproductive, but potentially destructive.
Mixing up love with food in this manner carries a lot of emotional risks. The primary one is immense guilt when you fail, but there is also the potential for resentment of the person you're hoping to benefit with your weight loss. Since food issues are intensely personal, linking your food and lifestyle choices to other people is placing control and motivation outside of yourself. It's a tenuous motivation. If your spouse makes you angry, are you going to decide it's not worth it and binge only to be filled with regret and remorse later when a level head returns and emotions are quiet? One needs consistent motivation, and looking to others for that is not going to be very effective.
I would encourage anyone who thinks others should lose weight for their sake, or who thinks they should lose weight for the sake of the ones they love to look inside themselves for motivation and not to associate food choices with personal valuation. People can't and shouldn't be blackmailed into losing weight in this manner and attempting to do so will make it all that much more painful when there is failure. Your body and food are an entirely different order than your love for those who are dear to you. The needs and desires of your body and mind cannot be placed aside for the greater interests of others. They need to be dealt with for yourself.