4. Volumetrics diet

A diet that's also based on low-energy-dense foods, Volumetrics menu items are large in volume but low in calories. That's thanks to a whole lot of fruits, vegetables, whole grains, nonfat dairy, and lean meat. Volumetrics manages to meet or come close to recommendations for the majority of nutrients you need, making it a safe, healthy-eating approach. Click here for the full review.

Score: 4.5

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