Walnuts may help you lose weight and make better food choices.
Gaining weight is complicated, but it is not less complicated than losing it. Weight gain is a consequence of total energy intake. It is an imbalance between what we eat and burn during our lives. If we burn more, we lose weight, and if we burn too little, we gain weight. It is simple in concept yet complex in reality. At the population level, consuming foods, such as nuts, would appear to be inversely associated with increasing weight because they are very dense in calories. The reasons for the difference are unclear, but they could be examined in the context of dietary advice for weight loss.
In a 2017 study, researchers hypothesized that including walnuts in dietary advice influenced other food choices and overall weight loss. They planned to examine the impact of consuming walnuts in a weight loss intervention on body weight. The researchers used data from a previous study, Health Track, to look at the impact of walnuts on weight loss and food consumption. The subjects were overweight and obese adults from Australia. Participants were randomized to receive either general dietary advice (the control group), individualized dietary advice (the intervention group), or individualized advice including a supplement of 30 grams walnuts/day. The researchers looked at changes in body weight and intake of key foods. The researchers found that walnut consumers achieved the greatest weight loss. This group also reported significantly greater increases in intakes of fruit products and dishes and decreases in intakes of processed foods.
The bottom line: The intake of 30 grams walnuts appears to result in increased weight loss and better dietary choices such as more fruits and vegetables and fewer processed foods. This study is right in line with the prior research I reviewed on walnuts. I also wrote a weight loss tip article on walnuts. I would recommend walnuts as a supplement to a healthy diet and this is just one more study to support this recommendation.
One weakness of this study is that is was funded by the California Walnut Commission.