‘ DOUBLING SATURATED FAT IN THE DIET DOES NOT INCREASE FAT IN THE BLOOD – STUDY ‘


#AceFoodNews – OHIO (Columbus) – Nov.27 – Doubling or even nearly tripling saturated fat in the diet does not drive up total levels of saturated fat in the blood, according to a controlled diet study.

However, increasing levels of carbohydrates in the diet during the study promoted a steady increase in the blood of a fatty acid linked to an elevated risk for diabetes and heart disease.

The finding “challenges the conventional wisdom that has demonized saturated fat and extends our knowledge of why dietary saturated fat doesn’t correlate with disease,” said senior author Jeff Volek, a professor of human sciences at The Ohio State University.

“It’s unusual for a marker to track so closely with carbohydrate intake, making this a unique and clinically significant finding. As you increase carbs, this marker predictably goes up,” Volek said.The researchers found that total saturated fat in the blood did not increase – and went down in most people – despite being increased in the diet when carbs were reduced. Palmitoleic acid, a fatty acid associated with unhealthy metabolism of carbohydrates that can promote disease, went down with low-carb intake and gradually increased as carbs were re-introduced to the study diet.In the study, participants were fed six three-week diets that progressively increased carbs while simultaneously reducing total fat and saturated fat, keeping calories and protein the same.

When that marker increases, he said, it is a signal that an increasing proportion of carbs are being converted to fat instead of being burned as fuel. Reducing carbs and adding fat to the diet in a well-formulated way, on the other hand, ensures the body will promptly burn the saturated fat as fuel so it won’t be stored.

“When you consume a very low-carb diet your body preferentially burns saturated fat,” Volek said. “We had people eat 2 times more saturated fat than they had been eating before entering the study, yet when we measured saturated fat in their blood, it went down in the majority of people. Other traditional risk markers improved, as well.”

The research is published in the Nov. 21, 2014, issue of the journal PLOS ONE.

Volek and colleagues recruited 16 adults for the study, all of whom had metabolic syndrome, defined as the presence of at least three of five factors that increase the risk for heart disease and diabetes (excess belly fat, elevated blood pressure, low “good” cholesterol, insulin resistance or glucose intolerance, and high triglycerides).

After getting them to a baseline reduced-carb diet for three weeks, researchers fed the participants the exact same diets, which changed every three weeks, for 18 weeks. The diets started with 47 grams of carbs and 84 grams of saturated fat each day, and ended with 346 carb grams per day and 32 grams daily of saturated fat.

Each day’s meals added up to 2,500 calories and included about 130 grams of protein. The highest-carb level represented 55 percent of daily calories, which roughly matches the estimated daily percentage of energy provided by carbs in the American diet.

Compared to baseline, there were significant improvements in blood glucose, insulin and blood pressure that were similar across diets. Participants, on average, lost almost 22 pounds by the end of the trial.

When looking at palmitoleic acid, however, the scientists found that it consistently decreased on the high-fat/low-carb diet in all participants. The fatty acid then showed a step-wise increase in concentration in the blood as carbs were progressively added to the diet. Elevated levels of palmitoleic acid in the blood have been linked to obesity and higher risk for inflammation, insulin resistance, impaired glucose tolerance, metabolic syndrome, type-2 diabetes, heart disease and prostate cancer.

The study does not address what happens to palmitoleic acid levels when high carbs are combined with a diet high in saturated fat. Instead, Volek hoped to identify the carb-intake point at which participants began to store fat.

“That turned out to be highly variable,” he said. “Everyone showed increased palmitoleic acid levels as carbs increased, but values varied widely between individuals, especially at the highest carb intake. This is consistent with the idea that people vary widely in their tolerance to carbohydrates.”

Participants’ existing health risks were not a factor in the study because everyone ate the exact same diet for 18 weeks. Their bodies’ responses to the food were the focus of the work.

“There is widespread misunderstanding about saturated fat. In population studies, there’s clearly no association of dietary saturated fat and heart disease, yet dietary guidelines continue to advocate restriction of saturated fat. That’s not scientific and not smart,” Volek said. “But studies measuring saturated fat in the blood and risk for heart disease show there is an association. Having a lot of saturated fat in your body is not a good thing. The question is, what causes people to store more saturated fat in their blood, or membranes, or tissues?

“People believe ‘you are what you eat,’ but in reality, you are what you save from what you eat,” he said. “The point is you don’t necessarily save the saturated fat that you eat. And the primary regulator of what you save in terms of fat is the carbohydrate in your diet. Since more than half of Americans show some signs of carb intolerance, it makes more sense to focus on carb restriction than fat restriction.”

Volek sees this palmitoleic acid as a potential biomarker to signal when the body is converting carbs to fat, an early event that contributes to what he calls “metabolic mayhem.”

“There is no magical carb level, no cookie-cutter approach to diet, that works for everyone,” he said. “There’s a lot of interest in personalized nutrition, and using a dynamically changing biomarker could provide some index as to how the body is processing carbohydrates.”

This work was supported by the Dairy Research Institute, the National Cattlemen’s Beef Associationand the Egg Nutrition Center.

Co-authors include Brittanie Volk, Laura Kunces, Brian Kupchak, Catherine Saenz, Juan Artistizabal and Maria Luz Fernandez of the University of Connecticut; Daniel Freidenreich, Richard Bruno, Carl Maresh and William Kraemer of Ohio State’s Department of Human Sciences; and Stephen Phinney of theUniversity of California, Davis.

#AFHN2014

‘ The Five Basic Rules for Cooking Meat ‘


You can cook meat a number of different ways, from roasting to pan-searing to barbecuing. However, there are five basic principles that apply to the vast majority of techniques when it comes to meat and poultry. Here’s what we’ve found after years of cooking in our test kitchen:

1. USE HIGH HEAT TO DEVELOP FLAVOR

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Browning creates a tremendous amount of flavor and is a key step when cooking meat. This happens through a process called the Maillard reaction, named after the French chemist who first described it in the early 1900s. The Maillard reaction occurs when the amino acids and sugars in the food are subjected to heat, which causes them to combine. In turn, hundreds of different flavor compounds are created. These compounds break down to form yet more new flavor compounds, and so on, and so on. When browning meat, you want a deep brown sear and a discernibly thick crust on all sides—best obtained by quick cooking over high heat.

To ensure that meat browns properly, first make sure the meat is dry before it goes into the pan; pat it thoroughly with paper towels. This is especially important with previously frozen meat, which often releases a great deal of water. Second, make sure the pan is hot by preheating it over high heat until the fat added to the pan is shimmering or almost smoking. Finally, make sure not to overcrowd the pan; there should be at least 1/4 inch of space between the pieces of meat. If there isn’t, the meat is likely to steam instead of brown. If need be, cook the meat in two or three batches.

2. USE LOW HEAT TO PRESERVE MOISTURE

For large cuts of meat or poultry, we often advocate a low-and-slow cooking method. We find that this approach allows the center to come up to the desired internal temperature with less risk of overcooking the outer layers.

An experiment we recently conducted proves that even cooking isn’t the only benefit of slow roasting: It also helps minimize the loss of flavorful juices (and fat). We took two 6‑pound rib roasts and roasted one at 450 degrees and the other at 250 degrees until each was medium-rare. We then weighed the cooked roasts. The slow-cooked roast had lost about 9.25 percent of its starting weight, while the high-temperature roast had lost nearly 25 percent of its original weight. Why the difference? Proteins shrink less and express less moisture and fat when cooked at moderate temperatures than when roasted at high heat.

3. MATCH THE CUT TO THE COOKING METHOD

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Tough cuts, which generally come from the heavily exercised parts of the animal, such as the shoulder or rump, respond best to slow-cooking methods, such as pot roasting, stewing, or barbecuing. The primary goal of slow cooking is to melt collagen in the connective tissue, thereby transforming a tough piece of meat into a tender one. These cuts are always served well done.

Tender cuts with little connective tissue generally come from parts of the animal that receive little exercise (like the loin, the area along the back of the cow or pig). These cuts respond best to quicker, dry-heat cooking methods, such as grilling or roasting. These cuts are cooked to a specific doneness. Prolonged cooking increases moisture loss and can turn these tender cuts tough.

4. DON’T FORGET ABOUT CARRYOVER COOKING

Since the temperature of meat will continue to rise as it rests, an effect called carryover cooking, meat should be removed from the oven, grill, or pan when it’s 5 to 10 degrees below the desired serving temperature. Carryover cooking doesn’t apply to poultry and fish (they don’t retain heat as well as the dense muscle structure in meat). The following temperatures should be used to determine when to stop the cooking process.

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*These doneness temperatures represent the test kitchen’s assessment of palatability weighed against safety. The basics from the USDA differ somewhat: Cook whole cuts of meat, including pork, to an internal temperature of at least 145 degrees and let rest for at least 3 minutes. Cook all ground meats to an internal temperature of at least 160 degrees. Cook all poultry, including ground poultry, to an internal temperature of at least 165 degrees. You may read more information on food safety from the USDA.

5. REST YOUR MEAT

The purpose of resting meat is to allow the juices, which are driven to the center during cooking, to redistribute themselves throughout the meat. As a result, meat that has rested will shed much less juice than meat sliced straight after cooking. To test this theory, we grilled four steaks and let two rest while slicing into the other two immediately. The steaks that had rested for 10 minutes shed 40 percent less juice than the steaks sliced right after cooking. The meat on the unrested steaks also looked grayer and was not as tender. A thin steak or chop should rest for 5 to 10 minutes, a thicker roast for 15 to 20 minutes. And when cooking a large roast like a turkey, the meat should rest for about 40 minutes before it is carved.

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Now that you know the basic principles, try applying them to one of our recipes, likePepper-Crusted Beef Tenderloin Roast. It’s easy to make—just oven-roast it until it’s done—and, as the absolute most tender cut of beef, it’s luxurious to eat. We boosted the flavor with a crunchy peppercorn crust.

ilo_pork_primalcutsOn cimeatbook.com, find meat recipes, meat video tips, and all meaty matters regarding The Cook’s Illustrated Meat Book.

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