I was at a business lunch a few days ago and noticed something I’ve seen often: a woman ordered a large salad with no meat, no cheese, and with fat-free dressing. The salad came as this monster bowl of lettuce, cucumbers, tomatoes, peppers, broccoli, radishes, and beans. The lady dribbled no-fat dressing sparingly and began to eat. I’m sure she felt very noble consuming all these fresh and colorful veggies, and all without an added smidgen of fat to threaten her cardiovascular system.
She obviously doesn’t know the secret. What secret? The secret we wrote about in the Protein Power LifePlan six years ago.

Here’s a little secret that the makers of no-fat products and the promoters of low-fat diets are not likely to tell you: many of the most potent cancer-fighting nutrients in plants can’t be absorbed well without some fat accompanying them. Specifically, carotenoids found in colorful fruits and vegetables, and lycopene, found in tomatoes, require fat for their absorption. If you make a salad loaded with various greens, slices of cucumber and tomato, and diced bits of carrots and other colorful vegetables, then top it with one of the zillions of no-fat dressings available to the low-fat conscious, you will be missing out not only on taste but on many of the nutrients in the salad that you simply won’t be able to absorb without the fat. Make sure that when you eat a salad, you dress it with virgin or extra-virgin olive oil, canola oil, or nut oil, all of which contain a whole host of valuable nutrients and antioxidants. If you eat steamed vegetables, drizzle them with olive oil or melted butter, so that the fat-soluble nutrients don’t go unabsorbed.

In rereading that paragraph, I wouldn’t change a thing except that I would remove canola oil from the list of acceptable oils. Since writing the above in 1999 I’ve learned that canola oil, also called rapeseed oil, virtually always contains a fair percentage of trans fats, which are created during the deodorization process.
Here are a couple of recent papers on the subject of carotenoids and fat. The first from the American Journal of Clinical Nutrition shows that

High-sensitivity HPLC with coulometric array detection enabled us to quantify the intestinal absorption of carotenoids ingested from a single vegetable salad. Essentially no absorption of carotenoids was observed when salads with fat-free salad dressing were consumed. [My italics[ A substantially greater absorption of carotenoids was observed when salads were consumed with full-fat than with reduced-fat salad dressing.

You should be able to get the full text of this article from this site if you’re interested after August 1 of this year.
The second paper is from the Journal of Nutrition and concludes:

In conclusion, adding avocado fruit can significantly enhance carotenoid absorption from salad and salsa, which is attributed primarily to the lipids present in avocado.


  1. Both of the canola oils I have say that they have 0 grams of trans fat. Is canola still a problem?
    I have read a couple of papers showing that virtually all canola oil contains trans fats. Canola oil as it comes from the rape seed is a nasty smelling substance that must be deodorized before it can be consumed. During the chemical deodorization process, according to these papers, a portion of the unsaturated fats are converted to trans fats. The labels listing zero trans fats are probably correct in the fact that the canola oil hasn’t gone through the partial hydrogenation process to actually make trans fats, but is incorrect in terms of the trans fats that are there from deodorization.

  2. I find your response about canola oil to be a bit mindblowing. Are you saying that the nutrition label on the bottle of oil does not reflect the nutritional value of the end product, but instead reflects the nutritional value of the oil before deodorization? Or are you saying that the label is just plain wrong?
    I think the label is just plain wrong. I’ve read a couple of papers on the deodorization of canola oil (which smells and looks wretched as it comes from the seed), and both found that the process creates trans fats. I suspect that most processors don’t list trans fats on the label unless the oils have gone through the partial hydrogenation process. Unfortunately, that’s not the only way that trans fats are created.
    I’ve never had a sample of canola oil analyzed myself so I certainly wouldn’t bet my life that it all contains trans fats, but based on what I’ve read in the scientific literature, MD and I don’t use it any longer.

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