Low-fat diets can cause constipation
The problem with many low-fat diets is that people follow them too closely. The idea is that the body can’t burn fat if there is any carbohydrate consumed at all—and this just is not so.
Anyone who has lost weight on the lemon juice diet can tell you that it is still possible to lose weight even if you eat lemon, fruits, and vegetables. But the first two weeks of the Atkins plan tries to help dieters lose weight by inducing a process called ketosis. To achieve that you cannot eat over 20 grams of carbs per day.
That means not eating more than one small fruit or a starchy food serving about the size of a slice of bread or maybe 1/3 cup of rice, for your total carbs, for all day. If you did not eat the fruit or the starchy carb, then you could have three small servings of a non-starchy vegetable, like spinach.
For most people who stick to the Atkins diet, the resulting constipation is mild or severe. It is not unusual for people to walk around for days with bulging stomachs, belching, flatulence, and acid reflux. Weight measurements would be down, but waistline measurements would be up.
Even if the diet burned belly fat, constipation would keep the waistline from shrinking. That is the result of the very high fat intake that was allowed on the Atkins diet, like high fat cheese and a lot of meat, with very low fiber intake. And later scientific studies found that the ketosis the Atkins initiation diet was attempting to induce is not a requirement for burning fat, and, in fact, may be a negative for your health.
So enjoy a piece of fruit—even better after you have a refreshing glass of lemon juice and water.