Finding the Best Way to Cook All Those Vegetables

Processed tomato products have higher lycopene content than fresh tomatoes.

Boiling was better for carrots, zucchini and broccoli than steaming, frying or serving them raw.
Trade off: boiling carrots significantly increased measurable carotenoid levels, but resulted in the complete loss of polyphenols compared with raw carrots.

When salsa or salad were served with fat-rich avocados or full-fat salad dressing, the diners absorbed as much as 4 times more lycopene, 7 times more lutein and 18 times the beta carotene than those who had their vegetables plain or with low-fat dressing.

Source: New York Times: Finding the Best Way to Cook All Those Vegetables