I spotted a study on elderly diabetes patients in Japan and the effects of eating high quantities of veg and how green veggies can impact tryglyceride and waist circumference if eaten in large quantities. Results re-posted below. The conclusions seem to imply that those eating a high proportion of veg seemed to eat healthier overall.
I agree with @carorees, green veggies are not weight loss inducing per se, but are indeed vital when it comes to improving health.
http://www.ncbi.nlm.nih.gov/pubmed/22435940There were significant decreases in HbA1c, triglycerides and waist circumference with an increase of total vegetable intake. A significant decrease of HbA1c levels was observed in patients with a daily total vegetable intake of 150 g or more. Furthermore, there was a significant decrease of serum triglyceride levels in patients with a total vegetable intake of 200 g or more. HbA1c levels showed a decreasing tendency with the increase of green vegetable intake, and HbA1c levels in the Q1 group (green vegetable intake: less than 40 g) was significantly higher than those in the other four groups (anovaP = 0.025). In addition, there were significant decreases of body mass index, triglyceride levels and waist circumference with the increase of green vegetable intake. Triglyceride levels decreased significantly from the Q3 group (green vegetable intake: 70 g or more) to the Q5 group (green vegetable intake: 130 g or more; anovaP = 0.016). In the group with a lower intake of total vegetables and green vegetables, the protein energy ratio decreased significantly. As a result, the fat energy ratio and energy intake tended to increase with the decrease of total and green vegetable intakes. Furthermore, intake of grains, sweets and alcoholic beverages increased with the decrease of total vegetable intake. In contrast, intake of nuts, potatoes, sugar, legumes, fruit, seaweed and fish increased with the increase of total vegetable intake
CONCLUSIONS:
Daily total vegetable intake of 200 g or more, and green vegetable intake of 70 g or more correlated with improved control of HbA1c and triglyceride levels in elderly type 2 diabetes patients through achieving a well-balanced diet.