Intermittent fasting (IF) involves alternating periods of fasting (e.g., 16 to 20 hours) and non-fasting (e.g., 4 to 8 hours).  IF seems to be a fad lately within the fat loss and fitness industry.   Since intermittent fasters eat less frequently (e.g., 2 to 3 meals daily), they must eat a lot of food per meal in order to get an adequate caloric intake (can you say gluttony?!).  Eating so much food within a relatively short period of time inevitably makes the body work harder to digest the food.  
    Here are some of the PROS of IF:

• Decreases body weight--this is partly due to caloric restriction 
• Increases insulin levels--this is due to lower blood sugar levels which causes the pancreas to reduce its insulin release
• Increases human growth hormone (HGH) levels--increased HGH is released from the pituitary gland to allow the body to use more fat for energy  
  
• Decreases risk of diseases--this is partly due to hormone changes lessening the onset of diseases like cancer and heart disease
• Improves cholesterol levels--LDL and HDL levels tend to decrease and increase, respectively
• Decreases blood pressure--this is due to a decrease in resting metabolic rate

    Here are some of the CONS of IF:

• Catabolism--this occurs when muscle, which is a much more metabolically active tissue than fat, is broken down for needed energy when caloric intake has been reduced.  
• Hypoglycemia--this involves low blood sugar levels which causes symptoms of hunger, headaches, weakness, and irritable feelings
• Bulging full feeling--caused by eating a relatively large amount of food within a short period of time
• Lethargy--this is caused by a lack of energy (read:  calories) needed to fuel mental and physical activities
• Reduces Metabolic Rate--this is partly due to elevated cortisol, a stress hormone

      Bottom line:  IF may work for some people who are disciplined at dieting and and are able to withstand hunger pangs.   IF is NOT recommended for diabetics due to the fluctuations in blood sugar levels.  IF is also NOT recommended for bodybuilders who aim to preserve muscle mass when dieting.

    My recommendation:  "Listen" to the hormonal signals provided by your body which indicate hunger and eat.  There are easier ways to lose body weight without causing dramatic fluctuations in blood sugar levels.  Gradually reduce your caloric consumption while stepping up your physical activity.  Eating healthy and exercising regularly will lessen disease risk, improve cholesterol levels, and reduce hypertension without resorting to a trendy diet like intermittent fasting.