White bread vs brown bread
White bread is made is from wheat flour from which the bran and germ have been removed. This is where much of the nutritional bread value is. White bread is lower in zinc, fiber, thiamin, niacin, trace elements and "good" fats and oils. White bread in many countries has to be fortified with vitamins and minerals *by law* during the bread making process. These are usually sprayed into the mix. It's somewhat ironic that the nutrients that are removed from wheat are re-added by this means. Nature provides, we destroy, then add it back in via a man made form.
Once the bran and germ is removed, the flour is bleached using potassium bromate, benzoyl peroxide or chlorine dioxide gas. Potassium bromate is also known as Bromic Acid or Potassium Salt. It's an oxidizing agent, can be fatal if swallowed, is harmful if inhaled or absorbed through the skin and may also cause kidney damage. Benzoyl peroxide is another irritant that can kill animals, birds, or fish, and cause death or low growth rate in plants. Chlorine Dioxide is also a pesticide and even though it breaks down very quickly, it is ranked in the USA as one of the compounds most hazardous to the environment.
So even before the baker adds his chemical magic, there's some pretty solid cons relating to white bread. Another point to note is that anything that needs "refining" requires more energy resources to do so.
By the way, just because bread is brown in color doesn't necessarily mean it's brown bread in the traditional sense of the term, i.e. meaning whole wheat or wholemeal. Check out the ingredients on the bread that you buy and ensure that the first ingredient is whole wheat or wholemeal flour rather than enriched wheat flour or just wheat flour. Enriched/wheat flour is the same type of flour used in white bread. The presence of caramel also is an indicator that it's not true brown/wholemeal bread as caramel is used as a coloring agent. A couple of other ingredients to avoid if possible are fructose corn syrup and partially hydrogenated oil/fats; aka trans fats.The general rule of thumb is the less ingredients in the bread and the presence of wholemeal flour as the major ingredient, the better it is for you - and the planet.
From: White bread vs brown bread
White rice vs brown rice
The following chart shows the nutritional differences between brown and white rice. Fiber is dramatically lower in white rice, as are the oils, most of the B vitamins, and important minerals.
This chart clearly shows the nutritional superiority of brown rice over white.
From: What’s Not Right about White?
White sugar vs brown sugar
Although a cup of brown sugar has slightly more calories than white, brown sugar also contains 187 milligrams of calcium, 56 mg of phosphorous, 4.8 mg of iron, 757 mg of potassium and 97 mg of sodium, compared to only scant traces of those nutrients found in white sugar. All the good parts – the molasses, the vitamins and minerals – have been removed; there is practically nothing left but carbohydrates and calories.
Now that the days of white sugar being considered a status symbol are long gone, the refining is now done for purely commercial reasons; it allows the sugar to last longer in the warehouse and on the supermarket shelf. Of course, to protect the end user – that’s you – merchants can simply put a “Consume Before:” stamp on the package of unrefined sugar. But that also means a risk for the merchant should the unrefined sugar expire before it gets sold. Ultimately, it’s your health that pays the highest price.
From: What’s Not Right about White?