Sugar free processed food (sugar free gum, soda, cakes, jam, etc) contains various ingredients like aspartame which is decrimental to your health and linked to various nerve degenerative diseases. If you really must have it, then have the real thing- so if you really must, drink Coke instead of Diet Coke (Source).
Sugar free products also can make you crave for sugar.
If you are doing something bad to your body, it will see to it that you are miserable. So if you down yourself with tonnes of alcohol or smoke like a chimmey, you will feel rotten after that.
Most packaged fruit juice are very rich in sugar. You can get fat by just driking packaged fruit juice every day (don’t believe, read the label and try it for a week).
Low fat does not mean low in calories. PLEASE READ THE LABEL. To ensure the product sells, most manufacturers have to replace fat with sugar. So low calories processed food generally have higer sugar content.
If your kid is a bit hyperactive/ low attention span, check if you are feeding him/her too much sugar.
If you have mood swings, monitor your sugar intake (I don’t mean fruits but processed sugar).
Cereals, Jacob’s oatmeal biscuits (or most type of biscuits) are really high in calories. Taking cornflakes and all types of cereals not only gives you lots of calories & sugar, it turns your blood sugar outside down.
Still, you should not be skipping breakfast. Replace with oats and wholemeal bread (not white bread).
Vitamins, taken in tablet form, have been shown to work differently from natural occuring vitamins in natural/real food. Coming from a science background, I can confirm that ascorbic acid (Vitamin C) can be easily produced from inorganic chemics in the lab- and many people are eating that.
If you go for a crash diet/starving yourself without exercise, first, you lose water, then muscle (coz you don’t use it). You end up lowering your metabolic rate- that means much more difficult for you to lose weight in future.
The more muscle you have in your body, the higher your metabolic rate. If you do resistance training (lifting weights), the effects are long term coz your muscle will be burning fat (fat cannot burn fat) even though you are resting.