Many diet plans cut out entire food groups, which can create nutrient deficiencies as well as health problems. For instance, if the diet is very low in carbohydrates and you have type 1 diabetes or type 2 diabetes, it’s probably not a good fit. And if it’s too restrictive and you’re pregnant or breastfeeding, it’s not a good idea, either. Keep in mind that pregnancy is not a time for weight loss. Speak with your doctor before making any changes to your diet if you are pregnant or breast-feeding.
“Intermittent fasting can be really challenging if you have an ever-changing schedule,” adds Hultin. “If you're traveling and crossing time zones, it could be very difficult to follow. It might be best for people with more stability in their lives.” Intermittent fasting isn’t safe for people with type 2 diabetes, children, pregnant or lactating women, or anyone with a history of an eating disorder.
Fiber aids digestion, prevents constipation, and lowers cholesterol -- and can help with weight loss. Most Americans get only half the fiber they need. To reap fiber's benefits, most women should get about 25 grams daily, while men need about 38 grams -- or 14 grams per 1,000 calories. Good fiber sources include oatmeal, beans, whole grain foods, nuts, and most fruits and vegetables.