Numerous high quality studies have asked the question of whether consuming FV impacts weight management or weight loss but none of them looked at the totality of evidence for effects by sex. Therefore, this is the first comprehensive critical narrative evaluation of the role of FV in body weight and anthropometric measures focused on women. From the findings, there is probable evidence from prospective and longitudinal studies that increased total FV intake promotes long-term weight stability or loss compared to low total FV intake in women. Total fruit intake tended to have a stronger association with long-term weight stability or loss than total vegetable intake, as starchy vegetables were associated with increased weight over time. There is possible evidence that a serving of starchy vegetables promotes more significantly increased weight gain in older women compared to younger women, which is likely associated with hormonal changes, aging related loss of adipose tissue flexibility, or other metabolic changes (Figure 3
). Legumes consumed with low GL diets were more strongly associated with long-term weight loss compared to when they were eaten with high GL diets. The relative weight loss (%) in obese or overweight and normal weight women is generally the same but the net weight loss (kg) tends to be higher in obese of overweight women because of the higher baseline weight.
Data from 12 primary RCTs, six weeks to 24 months in length, also support a role for the increased intake of FV to reduce body weight, BMI, waist, and hip circumference, or body fat in overweight or obese premenopausal women compared to a variety of control diets. Overall, in premenopausal women, there is probable evidence from RCTs that increased intake of FV can lead to weight loss, especially with a concurrent reduction in foods rich in energy or fat. It is also probable that increasing consumption of healthy FV alone can contribute to weight stability or modest weight loss that is similar but not as effective as energy-restricted weight-loss diets. A non-energy restricted diet, including starchy vegetables, fried potatoes, and 100% fruit juice as part of the total FV intake, limits the amount of weight loss. The addition of high amounts of FV and 100% fruit juice to energy-restricted weight loss diets does not tend to change the amount of weight loss compared to weight loss diets low in FV or without 100% juice in women. Eight RCTs using three different dietary approaches consistently support an essential role for the increased intake of FV in preventing long-term weight gains or promoting reductions in weight, BMI, WC and/or body fat in overweight or obese postmenopausal women over six weeks to 7.5 years compared to a variety of control diets. Seven RCTs consistently supported a role for the increased intake of the group of vegetables known as legumes in preventing long-term gains or promoting reductions in weight, BMI, WC and/or body fat in overweight or obese women over eight weeks to one year with non-energy-restricted, weight maintenance, or weight-loss diets.
In obese and overweight women, weight gain occurs if energy intake is higher than energy expenditure [83
]. Compared with most other foods, the volume of FV in relation to the energy content is higher. Because of the favorable ED of FV, satiety signals are triggered without consuming a large amount of energy. There are a number of biological mechanism linked to FV regulation of hunger and energy intake for body weight control or loss. Whole FV have a macronutrient nutritional profile that helps to promote neutral or negative energy balance by slowing the rate of eating and increasing satiety. Most FV varieties are considered very-low to low ED, have low GL and little dietary fat content, are good sources of dietary fiber, and an essential source of vitamins, phytochemicals, and minerals [2
]. All of these attributes can help promote neutral or negative energy balance to reduce the odds of long-term weight gain and support healthy body compositions and weight loss, especially with concurrent restriction of the intake of high ED or high-fat foods, and increasing fiber intake toward recommended levels [2
]. Yet, it is crucial to consume the right FVs that can best impact weight control in women (Figure 1
, Figure 2
and Figure 5
). Fruits or non-starchy vegetables are generally high in bulk volume, less than 100 kcals per serving, and very low or low in ED, mainly because of their physical structure, including high water content and fibrous plant cell walls, and lower fat content and GL [2
]. These FV attributes may assist women in achieving slower eating rates, which were associated with less weight gain or regain after weight loss and lower BMI compared to women with fast eating rates [5
]. FV juices (100%) have similar micro-nutritional and phytochemical composition to the whole FV but without the fiber or physical cell wall bulking structure and with a higher GL (e.g., a medium apple has a GL 6 vs. a GL of 10 for unsweetened, reconstituted apple juice; or a medium orange has a GL of 4 vs. a GL of 9 for unsweetened reconstituted orange juice) [85
]. Dried FV tend to have similar nutritional composition as whole FV but with higher ED and GL as the water has been removed. An increase of a serving/day of high GL vegetables was not associated with weight change (−0.005 kg) compared to weight loss of −0.15 kg for an increase serving/day of low GL vegetables over 4 years from a study of 86% women [18
]. Fried FV are higher in total energy, ED, and fat, which replaces most of the water. Intake of starchy vegetables such as potatoes, especially French fries, or sweet corn, increases the risk of long-term weight gain [17
]. High fiber vegetables including white potatoes (baked, boiled, or mashed) are associated with no weight change 0.0 kg (−0.09 to +0.09 kg) but excluding white potatoes from higher fiber vegetables is associated with weight loss −0.09 kg (−0.03 to −0.14 kg) per increase serving over 4 years [18
]. The top consumed FV do not necessarily contain the more essential nutrients associated with weight control, so there are opportunities to improve the quality of FV consumed.