Claiming cooked meat is more nutritional and raw meat wastes calories

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Claim: Cooked meat is not more nutritious than raw meat, nor does it give you more calories.

In the Iceland episode, Bear claims that cooked meat is more nutritious and gives you more calories than raw meat. While there are many reasons to cook meat first (most of them microscopic and wriggling), this is not one of them. Cooking foods denatures elements unevenly. Denaturing some things is beneficial -- for example, cell walls, allowing the contents of the cell to be digested. Denaturing others is harmful, such as vitamins and minerals (cooking meat, for example, reduces its B12 content[1])

In a famous series of experiments, Francis M. Pottinger demonstrated that cats cannot effectively survive on an unsupplemented cooked-meat diet.[2] Modern cat foods, while cooked, are heavily supplemented with nutrients like taurine that are destroyed in the cooking process. Most proteins are, to some degree or another, succeptible to heat denaturing. Likewise, cooking increases the amount of carcinogens and mutagens in meat, such as heterocylic amines[3].

Of course, these are all long-term survival issues. What about the pressing short term, issue: calories?

From a basic energy standpoint, any chemical change from cooking of the meat that's not an (extremely unlikely) endothermic reaction is reducing the energy content of the meat. Cooking does drive off water (hence the reason that a quarter pound patty isn't still a quarter pound after cooking), making the energy density per unit mass higher. This may have been what confused Bear.

Of course, total energy content isn't what matters. Biologically available energy is what matters. Can cooking increase biologically available energy? Animal cells don't have cell walls -- only cell membranes. Cell membranes are trivial to rupture by the digestive system, and so cooking doesn't increase the amount of nutritive content that can be extracted from the meat. On the other hand, cell walls from plant-based foods are a significant obstacle to digestion, as we cannot digest cellulose.[4] Cooking that ruptures them (making the cooked vegetable soft as a side effect), increasing the nutrient bioavailability. Many references can be found here.

As an example, compare raw versus cooked meat on table 2-11. You'll notice that there is a constant slight increase in calories per gram when meat goes from raw to cooked. However, the meat's caloric density is also increasing simply from having its water driven off. So, if we take, say, raw beef brisket (62% water, 2.5 calories per gram) and compare it to boiled beef brisket (48% water, 2.9 calories per gram) on a gram per gram basis, the cooked brisket has 16% more calories. However, that gram of cooked brisket originally was, at a minimum, 30% more massive. Thus, overall, the meat lost calories in the cooking process. If you look at meats which don't significantly lose water in cooking, there is always a caloric decrease.

[edit] Analysis

Oppose: Either way, he is setting a good example by telling you to cook your meat.

Oppose: The digestion of protein is an energy intensive process, especially for non-carnivorous species such as man. Cooking meat greatly reduces this requirement.

Support: And your references which counter the references above which directly state that this isn't the case are...? The references are clear: cooked meat has less calories per non-water gram, and digesting animal matter is relatively easy for the body (unlike plant matter) because all it has to do is rupture the cell membrane to expose the proteins, and that's very easy (unlike breaking down a cell wall). Pepsin and trypsin have very little trouble breaking down the vast majority of proteins once released into amino acids, which can be used directly or converted to energy. Cooking proteins typically won't even denature them as much as pepsin alone generally does. Humans are omnivores, not "non-carnivores"; we're adapted to eating meat, and have been eating extensively for the past two million years. There's no evidence for the regular, controlled use of fire for cooking until 300k-400k years ago. I.e., for around 1.6 million years (almost 100,000 generations), our ancestors were eating meat without cooking it. You don't go for a hundred thousand generations on a certain diet without adapting to it. Our adaptation to eating meat is largely credited with allowing us to sustain the larger brains that led to the intelligence and success of our species.

Oppose: Bear has eaten raw meat numerous times. Cooking also kills germs.

Support: Whether or not it kills germs (as was mentioned in the article) and whether or not he's done it before doesn't change the fact that he made a false statement.

Support: Raw meat would also have more calories as when you cook meat, a lot of the fat drains off of it.