Hello and I hope you're training is going well. I have found great success with my clients who maintain a diet of whole foods that are unprocessed, avoiding caffeine and alcohol, lots of veggies and fruits. However, we do believe everything in moderation! I do support the addition of protein smoothies for breakfast and lunch when trying to shed some pounds. They help curb your cravings and reduce your appetite.
The only products I have found the most clinical research on would be Juice Plus which is whole food nutrition, including juice powder concentrates from 25 different fruits, vegetables and grains. They also have an awesome powder for your smoothies. We have introduced The Juice Plus Energy Program for those interested in losing weight. You can visit my website's to learn more and if you want to hear from one of our doctors who is a triathlete, scroll down to Dr. David Phillips. www.mdill.juiceplus.com
Good luck to you!