Can cooked food be bad for you? The science, and the food, behind Boston’s raw food restaurant.
Anna Kushnir
Boston’s North End has been the home of Italian restaurants for generations. This February’s opening of Grezzo is a departure for this historic neighborhood. Grezzo is Boston’s first raw vegan restaurant, serving foods that have not been heated above 112 ^˚^F (44 degrees Celsius) and contain no animal or animal-derived products.
Each table at the restaurant is set with a laminated card listing 40 reasons to eat exclusively raw foods. These include avoiding nutrient loss from cooking and preventing the destruction of active enzymes in the food. The card also claims a raw food diet can cure a host of diseases such as diabetes and cancer, and increase overall health, appearance, and general wellbeing. More than just a diet, raw food is a lifestyle choice. Many raw foodists consider uncooked food to be “living food” that can nourish the body in ways that cooked, or “dead,” food cannot.
Alissa Cohen, the owner of Grezzo, is well known in the raw food world. Her website explains what she and other raw foodists think is behind these physical and spiritual benefits. She says that cooking destroys enzymes in food. “[This] is a problem because we need enzymes for every function in our body.” Raw food replenishes the finite reserve of enzymes in our bodies, according to the website.
Cohen’s use of scientific terminology begs the question: what is the science behind the raw food movement?
When asked whether people need enzymes found in raw foods for health and digestion, Roberta Durschlag, the director of programs in nutrition at Boston University, suggests that if raw foods contained active enzymes, they would not remain functional after passing through the acidic environments of the stomach and small intestine. “Enzymes are proteins and are going to be digested in the stomach,” she says. “None of the enzymes are going to be absorbed [in a functional form]. Once the food leaves the stomach, you don’t have any enzymes.”
Could raw food be richer in nutrients than cooked food? There is some evidence to suggest that heating food can reduce its nutrient content, depending on the type of food and the method and duration of cooking. For example, certain water-soluble vitamins, such as vitamins C and folate (important for fetal development), can leech into cooking water during boiling, in addition to being inactivated by heat, resulting in total nutrient losses as high as 60 percent, depending on the food (Leskova et al, USDA). Minerals such as zinc and copper, and vitamins such as niacin, on the other hand, are relatively unaffected by conventional cooking techniques.
Conversely, cooking can actually aid in the absorption of other nutrients, such as beta-carotene (the precursor of vitamin A), which is important for vision and immune function. In one study, researchers found that women absorbed more beta-carotene from heat-treated carrots and spinach than from untreated, unprocessed vegetables (Rock et al).
Food first
Science aside, Grezzo is a restaurant, so perhaps the more important question is: how is the food?
To start off, the dining atmosphere is unique. The chefs at Grezzo rely on dehydrators, blenders, and juicers to create beautifully presented and colorful dishes, all at or below room temperature. The tiny kitchen, devoid of stoves, burners, and clanging pots and pans, lends an air of serenity to the restaurant. One leaves feeling calm and full, but not fully satiated. This is surprising, considering the high fat content of the nut-based “cheeses” and “milks” that stand in for traditional dairy and egg-derived products.
Grezzo’s gnocchi carbonara is a raw vegan interpretation of an Italian classic, substituting nuts for cooked potato dumplings and cashew milk for the traditional egg-laden sauce.
The gnocchi carbonara is made up of cashew and pine nut dumplings in a cashew milk sauce, with dehydrated eggplant bits as replacements for bacon or pancetta, and fresh English peas for contrasting texture. The “gnocchi” themselves are smooth and creamy, with an intense nutty, almost falafel-like taste, while the nut milk sauce is rich but not heavy, as an original carbonara would certainly be. Overall, the dish has very little to do with the familiar carbonara, but it is difficult to stop eating.
Tangy homemade pickles rescue the lackluster papaya steak.
The papaya steak, with its promising name, is simply a large piece of fruit, carved to resemble a filet of salmon and lightly dusted with ground star anise. It tastes pretty much like a papaya.
The Land and Sea, a raw mushroom ragout atop almond milk “ricotta” and kelp is delicious. In the absence of heat, the various mushrooms remain distinct, each with its own flavor profile, while the ricotta is remarkably full-bodied and creamy. However the mushrooms leave a persistent bitter aftertaste, one not typically experienced with cooked mushrooms.
The rich brownie sundae is raw foodism at its best–rich but not cloying.
All is forgiven with the arrival of the fudge brownie sundae. The dense brownie, made from raw carob, coconut, and yet more nuts, is a chocolate dream. The vegan, coconut water-based gelato atop the brownie is light and just sweet enough to complement, but not compete with, the brownie.
Grezzo may not be the best lesson in nutritional science, but it does make you pause and think about what you are eating and why you are eating it. It’s worth returning to—if not for the enzymes, then for the food itself.
On the one hand it looks like Grezzo is doing something really interesting in specialist cuisine, and on the other hand Alissa Cohen should be ashamed of her appalling use of pseudoscience. No doubt psychologists out there would have something to say about why Alissa feels the need to justify her cuisine in this way.
Where’s Ben Goldacre when we need him? He could, er, get his teeth into this.
Interesting discussion, and well documented. Indeed, the digestion begins in the stomach at pH 3. But not all the proteins are affected, or inactivated by trypsin. You may consider prions as prototypes of acid resistent protein. Papain from papaya is used as supplement to aid digestion, specially i nelderly peopel. I study the potato family of Kunitz-type proteinase inhibitors (PKPIs) from tomato, pepper, eggplant and potato, but present also in soybean. They denature under heating, but renature after that, and bind protease without being cleaved. Many individuals consuming potatoes have a high titre of IgGs specific to PKPIs. It is speculated that PKPIs enter the gut barrier passing through microvilli gaps, or by uptake from the Peyer plaque cells.
I’d like to express my expectation on the gastronomy. I could like some of the dishes at Grezzo, near my everyday style of feeding. Salads (spinach, alfaalfa and other sprouts) mainly. Carub chocolate is an old recipe in Modica, Sicily.
Raw mushroom salad, oil and lemon, can be made with certain type of mushrooms growing on the cortex of oak trees. These are really tasteful. I haven’t tried other types, maybe the dried shiitake.
Algae as nori and wakame are thought to be eaten raw. Tofu was a main vegetarian food for buddhist monks.
Pickled vegetables may be preserved for long time, just for the presence of lactic acid. Tsukemono are delicious, try them with rice (steam-cooked).
It is possible to cook food at 44 degrees C if you prolong the stay in a waterbath for 24 hours. You could even make cheese at 37-42 degrees. The point is the safety of food. Brief pasteurization /heat treatment helps in destroying bacteria, especially in milk. But this is not a food base in vegan cuisine.
However, from the pictures, the dishes look good, and your satisfaction witnesses it.
Matthew – Yes, some of the supporting evidence for why people should eat raw is based on questionable science. I can understand perfectly well the benefits of eating fresh, uncooked, or lightly cooked food – presenting it as scientifically sound seems unnecessary and risky.
Palmiro – Very good point about prions. They do remain ‘active,’ or in one piece, after passing through the stomach. However, even if some ingested proteins remain active in the stomach (or renature in the small intestine), I think it is still a stretch to say that they can aid in human digestion or other functions. I don’t know of any evidence that plant enzymes (I use plants as an example because most raw foodists are also vegan) can perform the same functions under the same conditions as the enzymes involved in human digestion. Is there evidence to indicate this?
The raw seaweed at the restaurant was wonderful. I really enjoyed it. There were a few pickled things, though raw foodists have to be careful not to use any cooked vinegars. Very curious about the waterbath incubation as well. I suppose a sous vide method would work well for this type of cuisine, provided that the temperature is very carefully controlled. It is interesting to point out that the temperature at which food is still considered raw varies among raw foodists – I have seen temperatures from 108F to 118F (42.2C – 47.8C) considered permissible.
Well, I did say something, but NN ate it. It likes its comments raw.
<I don’t know of any evidence that plant enzymes can perform the same functions under the same conditions as the enzymes involved in human digestion.>
This is true for papain, for instance.
In any case, either you count on your own digestive enzymes or you support them with plant proteases, the effect on food will be the cleavage of proteins into peptides, and this may be the interesting aspect, the production of bioactive peptides from meat, fish, hemoglobins, soy proteins, etc… some of them are anti-hypertensive, other are opiod-like, other can be useful to fight dental carie (caseinomacropeptide).
So the main concern is to not overload the stomach with those raw plants possessing too many protease inhibitors. And second, to understand which plant enzymes are of benefit, and which are not (artichokes, quince fruit) and in need of bleaching to block the enzymes before get involved in polyphenol oxidase/tannin reactions. You may think of the difference between using green tea and green tea powder (healthy even in cold wwater), compared to eat unripen fruits as sorbs, quinces.
Each type of plant should be used at the right time and with the more appropriate processing system (our elder people know well since they passed each other their experience).
But that’s another story!
Henry,
that’s about herbivores… global warming cathastrophe. Anna, your dishes look good, and the talk was fun
I must protest, the idea of eating only raw food is not based on questionable science, it is based on errors and faulty reasoning and not based on science at all. If a diet cannot do that, that diet cannot be considered “healthy”.
No hunter-gatherers have ever been found to live without cooking some foods. People who try and subsist on only a raw diet while hunting and gathering at a well-stocked first world supermarket lose weight and women become amenorrheic. A society that had to raise and/or gather its own food could not sustain itself long term without cooking.
There is a paper, Cooking as a biological trait (pdf 137 kb) which points much of this out in considerable detail.
I don’t doubt that one would lose weight. I don’t doubt that an otherwise healthy adult could manage such a diet for a while, but could a growing child or a lactating woman? A healthy diet must be able to sustain the entire population, including infants, sick and infirm individuals under harsh conditions for their entire lifetime and for many generations.
There is a misplaced line in my comment above. The sentence “If a diet cannot do that, that diet cannot be considered “healthy”.” should be moved from the end of the first paragraph to the end of the comment.