This is an interesting subject. In the West, we have the 'problem' of overeating and lack of exercise, which leads to the deposit of fat cells in our bodies.  If we were Inuit or other tribesmen, we would be pleased.  A store of fat will see us through the harsh winter. It would show that we were clever enough to obtain more food than normal. We can get others to do our bidding, so we don't need to work hard or hunt.  It would show that we were healthy, and had no internal parasites.  Fat is an attractive feature.

This however does not apply in the West. We find being overweight abhorrent, as we can now choose when, where, and what we eat, and we have central heating.  

So to be overweight is a sign of gross self-indulgence.It also signifies our class, as the poor and working classes tend to console themselves by eating junk food.

Be aware that body types come in and out of fashion.  At the time of writing to have almost no fat at all on your body is considered attractive. In the 1960's a well rounded woman with peroxided hair was an icon of beauty. Now anoexia in women and large pectoral muscles in men (called 'disco tits' by homosexuals) are the desired forms. In a few years this will change again.

We seek to ape fashion in the belief that it will make us more attractive sexually, more employable, and more authoritative.  It's display behaviour.  Some birds put the moulted feathers of more exotic birds in theirs, to make themselves more attractive to the opposite sex.

Also be aware that medically speaking being slightly over-weight is not harmful. The reverse, being underweight, and losing weight quickly, IS harmful.  You need a balanced diet to keep your body going.  The body in turn affects the mind. If you are well and wholesomely fed you feel better mentally.  If not, you feel tired and grumpy, and this can affect your work and personal relations.

What IS bad is bad about being grossly overweight, and eating 'junk' food?

What is gross overweight?  I define it as being unable to walk up two flights of stairs without panting, or being unable to run for a bus without similar results (assuming you are healthy in other respects).

It's not a matter purely of size, it's a matter of fitness.  If you can't see your own genitalia by looking straight down, you're overweight.  There is also the height-weight ratio.

If you are grossly overweight it's likely that the arteries feeding your heart are being furred up with fatty deposits over the years, which may lead to a heart attack.

Your heart also has to do more work to pump blood around your body. Your skeletal system has to support more weight, hence you may get backache. More seriously you become a target for other human beings, because you look different, and they know you're slower and can't run after them and beat them up!

This is the main problem; you're sending out a signal that you're slow and lumbering. 

In the event of crisis, you'll not be able to outrun it. In the event of a hunt, you'll not be able to run after the prey. You're a liability.  That makes you unattractive.

Being overweight in our Western society also signifies a lack of self-control; we have lots of food, but you can't moderate your eating.

It's also a pointer to your class; working class people tend to pile on AND KEEP ON the kilos, as they can't afford personal trainers and expensive, healthier foods to get their weight back down.

What is junk food? I define junk food as food which is highly processed, fatty, sugary, or chock-full-of-additives. With this food you aren't nourishing yourself, and are storing up health problems for later.

A quick rule of thumb :

The fancier, more garish, more moronic, and more expensive the packaging,
And the longer the process of manufacture,
And the greater the number of ingredients,
And the greater the number of these ingredients that are not food in themselves,
And the higher proportion of sugar, fat and salt...

The more likely it is be be 'junk'.

The further from the field it goes, the crappier it becomes, until one can eat crisps (potato chips) and drink colas which are almost completely removed from anything our ancestors might have recognised as edible or potable.

Pigs will not drink chlorinated water if they can help it. Animals will turn their noses up at our 'snacks'. They may not be so dumb after all.

So, what to do if you want to wear the slinky black dress, or not spill out of your business suit?

Five things:

1. Make sure first that you're not being neurotic and overly body conscious.

Meditate. Try to catch yourself naked unawares in a full length mirror. Find out your ideal height-weight ratio. Get some amateur photos taken of yourself in casual dress. Try and be detached and objective.

Overweight is sometimes a state of mind instead of body. What trauma or childhood inadequacy causes you to see yourself as fat and undesirable, when medically you're normal, or just a little full figured?

The most extreme example of this is anorexia; the perception of being overweight, based on self-hatred and self-doubt, which turns into a killer psychological disease.

The sufferer goes so far in dieting that the body in effect rules and ruins the mind, and they can't be persuaded back to normal eating patterns. They achieve their subconscious goal - extinction.

If you are definitely a fatty:

2. Meditate. Try to home in on the reason you are overweight.

Is it genetic; are your family 'big-boned'? If not, what need are you trying to fill by stuffing yourself; are you anxious, insecure, do you have family or money or sexual troubles? If so deal with THEM and your need to eat will be easier to beat.

Eating is pleasurable; we get a rush of blood sugar which makes us temporarily feel good, and having a full stomach makes us feel sleepy and calmed down. Are you going for the effect rather than the nourishment?