Eating apples may promote satiety and weight loss.  

Apple with Measuring Tape

Most Americans do not meet the recommended daily consumption of fruit consumption.   Apples are the second most commonly consumed fruit in the United States and have long been promoted as a good to promote improved general health and a slimmer waistline, however, few studies have examined the association of total apple products on diet quality and body fat.  Fruit is a nutrient-dense food, and it is a decent source of fiber.  Recent research has recommended increasing the number of servings you take per day to 6 or more, and eight or more are tied to lower risk of heart disease[1].   Fiber definitively help with weight loss so it makes sense that apples would help with weight loss.  

What does research show?

1. Apple products and BMI: One study looked at children and apple consumption[2].  The subjects were over 13,000 children who participated in dietary recall questionnaires.  Approximately 26 % of the population (n = 3,482) consumed some form of apple products. Consumers of apple products such as whole apples, applesauce, and 100 % apple juice were less likely to be obese than non-consumers.  
2. Granny Smith apples change gut bacteria.  Researchers found that Granny Smith apples have nondigestible compounds that changed the proportions of fecal bacteria from obese mice to be similar to that of lean mice[3].  It has already been proven that if obese mice have fecal microbiota similar to lean, they lose weight[4],[5].
3. Apple consumption can cause weight loss in as little as 4 weeks.  A review of prior studies that looked at apple consumption and weight[6].  They found that whole apple or apple juice consumed for 4-12 weeks by overweight subjects can cause weight loss.  
4. Apples appear to assist with weight loss with low-calorie diets.  Two studies looked at apple intake and weight loss and both found that low-calorie or weight-reduction diet combined with apples improves weight loss[7],[8].  One of the studies compared apple diets to similar calorie and fiber intake and found that apples were superior.
5. Apple pectin promotes satiety.  Soluble fermentable fiber pectin, like that found in apples, decreases food intake, body weight gain, and body fat content and it appears to induce satiety[9].

The bottom line: Apples are a healthy and fiber-filled fruit that do more than provide vitamins and calories.  Multiple studies show that they can assist with weight loss and help induce satiety.