Our style of eating has certainly changed over the years shows with the world-wide epidemic of obesity and type 2 diabetes.
We are no longer hunter/gatherers; they were slim as they primarily ate fiber from available vegetation and it was mostly eaten in it's raw form.
Protein was obtained from lean game that was killed and cooked almost straight away, with no fats or preservatives.
Not that we want to go back that far! Here are some clues as to how our blood sugar levels are affected by: Protein:

• contains no carbohydrates
• it does not raise your blood-sugars to a major degree
• actually stabilizes your levels
• in some people can help to decrease their levels
• when you don't eat enough protein, it is then easy to eat too many carbohydrates
• helps to reduce your appetite
• combined with exercise, burns more fat
• it also helps to preserve your muscle mass.
  Muscle tissue is efficient at burning fats and sugar.
  

Fiber:

• lowers your blood-sugar and stops it from rising quickly after your meal
• because it slows digestion it keeps you feeling full for longer
• it adds bulk to your meal, it's part of the carbohydrate that is not digested
• it adds no calories/kilojoules
• people who eat more are normally thinner than those who don't
• many of the foods listed as having a low glycemic index contain high fiber
• vegetables and fruit contain two types of fiber, soluble and insoluble.
  The soluble form dissolves in water and helps to reduce both blood glucose and cholesterol levels.
  Insoluble fiber is the one that remains in your intestine and helps prevent cancer and constipation.
  

Fats:

• many are essential for good health
• this includes polyunsaturated, eg.
  omega-3s and omega-6s which are found in fish, seeds, nuts and green leafy vegetables
• mono-saturates are found in avocados and olives
• your body also requires a very small amount of saturated fats
• to help with losing weight, cut back on your total fat intake and substitute healthy fats for not-so-healthy ones.
  

Maintaining a healthy weight and controlling your blood sugar levels is not always easy for people with type 2 diabetes Having a healthy balanced diet will help you lose weight, especially when combined with physical activity.