I’ve just listed the first 100 below, but Nancy Appleton gives an exhaustive list, including references, for the problems that result in over use of sugars, and for some of us even the small intake of refined sugars. 

For more see: http://www.healingcancernaturally.com/sugar-health-effects-risks.html

Sugar’s Health Effects, Risks & Problems: Is Sugar Sweet Poison?

146 Reasons Why Sugar Is Ruining Your Health

by Nancy Appleton, Ph.D., www.nancyappleton.com, author of Lick The Sugar Habit

In addition to throwing off the body’s homeostasis, excess sugar may result in a number of other significant consequences. The following is a listing of some of sugar’s metabolic consequences from a variety of medical journals and other scientific publications.

1 Sugar can suppress the immune system.
Compare Using Your Amuse System to Boost Your Immune System.

2 Sugar upsets the mineral relationships in the body.
Compare Minerals.

3 Sugar can cause hyperactivity, anxiety, difficulty concentrating, and crankiness in children.

4 Sugar can produce a significant rise in triglycerides.

5 Sugar contributes to the reduction in defense against bacterial infection (infectious diseases).

6 Sugar causes a loss of tissue elasticity and function, the more sugar you eat, the more elasticity and function you lose.

7 Sugar reduces high density lipoproteins.

8 Sugar leads to chromium deficiency.

9 Sugar leads to cancer of the breast, ovaries, prostate, and rectum.
[This statement may need to be qualified and reworded in less absolute terms, also see number 120, 126 & 143.]

10 Sugar can increase fasting levels of glucose.

11 Sugar causes copper deficiency.

12 Sugar interferes with absorption of calcium and magnesium.
Compare book extract.
In addition, sugar needs calcium to be metabolized and reportedly draws the required amounts from teeth and bones if these are not provided via food containing bioavailable calcium.

13 Sugar can weaken eyesight.

14 Sugar raises the level of a neurotransmitters: dopamine, serotonin, and norepinephrine.

15 Sugar can cause hypoglycemia.

16 Sugar can produce an acidic digestive tract.

17 Sugar can cause a rapid rise of adrenaline levels in children.

18 Sugar malabsorption is frequent in patients with functional bowel disease.

19 Sugar can cause premature aging.

20 Sugar can lead to alcoholism.

21 Sugar can cause tooth decay.

22 Sugar contributes to obesity.

23 High intake of sugar increases the risk of Crohn’s disease, and ulcerative colitis.

24 Sugar can cause changes frequently found in person with gastric or duodenal ulcers.

25 Sugar can cause arthritis.

26 Sugar can cause asthma.

27 Sugar greatly assists the uncontrolled growth of Candida Albicans (yeast infections).
Compare note on Candida Albicans in Fungi producing mycotoxins: The Fungal/Mycotoxin Etiology of Human Disease (particularly CANCER).

28 Sugar can cause gallstones.

29 Sugar can cause heart disease.

30 Sugar can cause appendicitis.

31 Sugar can cause multiple sclerosis.

32 Sugar can cause hemorrhoids.

33 Sugar can cause varicose veins.

34 Sugar can elevate glucose and insulin responses in oral contraceptive users.

35 Sugar can lead to periodontal disease.

36 Sugar can contribute to osteoporosis.

37 Sugar contributes to saliva acidity.

38 Sugar can cause a decrease in insulin sensitivity.

39 Sugar can lower the amount of Vitamin E in the blood.

40 Sugar can decrease growth hormone.

41 Sugar can increase cholesterol.

42 Sugar can increase the systolic blood pressure.

43 Sugar can cause drowsiness and decreased activity in children.

44 High sugar intake increases advanced glycation end products (AGEs) (sugar bound non-enzymatically to protein).

45 Sugar can interfere with the absorption of protein.

46 Sugar causes food allergies.

47 Sugar can contribute to diabetes.

48 Sugar can cause toxemia during pregnancy.

49 Sugar can contribute to eczema in children.

50 Sugar can cause cardiovascular disease.

51 Sugar can impair the structure of DNA.

52 Sugar can change the structure of protein.

53 Sugar can make our skin age by changing the structure of collagen.

54 Sugar can cause cataracts.

55 Sugar can cause emphysema.

56 Sugar can cause atherosclerosis.

57 Sugar can promote an elevation of low density lipoproteins (LDL).

58 High sugar intake can impair the physiological homeostasis of many systems in the body.

59 Sugar lowers the enzymes’ ability to function.

60 Sugar intake is higher in people with Parkinson’s disease.

61 Sugar can cause a permanent altering [of] the way the proteins act in the body.

62 Sugar can increase the size of the liver by making the liver cells divide.

63 Sugar can increase the amount of liver fat.

64 Sugar can increase kidney size and produce pathological changes in the kidney.

65 Sugar can damage the pancreas.

66 Sugar can increase the body’s fluid retention.

67 Sugar is enemy #1 of the bowel movement.

68 Sugar can cause myopia (nearsightedness).

69 Sugar can compromise the lining of the capillaries.

70 Sugar can make the tendons more brittle.

71 Sugar can cause headaches, including migraine.

72 Sugar plays a role in pancreatic cancer in women.

73 Sugar can adversely affect school children’s grades and cause learning disorders.

74 Sugar can cause an increase in delta, alpha, and theta brain waves.

75 Sugar can cause depression.

76 Sugar increases the risk of gastric cancer.

77 Sugar [can] cause dyspepsia (indigestion).

78 Sugar can increase your risk of getting gout.

79 Sugar can increase the levels of glucose in an oral glucose tolerance test over the ingestion of complex carbohydrates.

80 Sugar can increase the insulin responses in humans consuming high-sugar diets compared to low sugar diets.

81 High refined sugar diet reduces learning capacity.

82 Sugar can cause less effective functioning of two blood proteins, albumin, and lipoproteins, which may reduce the body’s ability to handle fat and cholesterol.

83 Sugar can contribute to Alzheimer’s disease.

84 Sugar can cause platelet adhesiveness.

85 Sugar can cause hormonal imbalance; some hormones become underactive and others become overactive.

86 Sugar can lead to the formation of kidney stones.

87 Sugar can lead to the hypothalamus becom[ing] highly sensitive to a large variety of stimuli.

88 Sugar can lead to dizziness.

89 Diets high in sugar can cause free radicals and oxidative stress.

90 High sucrose diets of subjects with peripheral vascular disease significantly increases platelet adhesion.

91 High sugar diet can lead to biliary tract cancer.

92 Sugar feeds cancer.

93. High sugar consumption of pregnant adolescents is associated with a twofold increased risk for delivering a small-for-gestational-age (SGA) infant.

94. High sugar consumption can lead to substantial decrease in gestation duration among adolescents.

95. Sugar slows food’s travel time through the gastrointestinal tract.

96. Sugar increases the concentration of bile acids in stools and bacterial enzymes in the colon. This can modify bile to produce cancer-causing compounds and colon cancer.

97. Sugar increases estradiol (the most potent form of naturally occurring estrogen) in men.

98. Sugar combines and destroys phosphatase, an enzyme, which makes the process of digestion more difficult.

99. Sugar can be a risk factor of gallbladder cancer.

100. Sugar is an addictive substance.