How Not to Diet

by Michael Greger

Flavones are plant compounds concentrated in herbs, vegetables, and fruits,1023 and the leading sources in the U.S. diet are parsley, bell peppers, celery, apples, and oranges.1024 The most flavone-filled beverage is chamomile tea.1025

The most pro-inflammatory food components are saturated fat and trans fat. Essentially, the top five sources of saturated fat in the United States are cheese, desserts like cake and ice cream, chicken, pork, and then burgers.

Thankfully, with the ban on added trans fat, the only remaining sources in the food supply will be the small amounts found naturally in meat and dairy and created in the refining of vegetable oils.1027

Ultimately, an anti-inflammatory diet in clinical practice first and foremost “focuses on eating whole, plant-based foods.”

By the time we hit early adulthood, the total number of fat cells in our bodies remains fairly stable.1054 When we gain or lose weight, we are pretty much just enlarging or shrinking our existing fat cells. Starting out with a higher number of fat cells or gaining more later in life may make it easier to put on pounds, harder to lose them, and more difficult to maintain weight loss.

What’s more, each fat cell we make may be at the expense of one fewer bone, cartilage, or muscle cell.

Some fish are worse than others. Halibut, swordfish, and canned tuna have been recorded as having the highest levels,1062 and a sampling of U.S. market-bought seafood found that farm-raised fish was generally worse than wild-caught.

Even once metabolized by the liver, which destroys the estrogenic effects, BPA retains the ability to promote adipogenesis, the process of creating fat cells.1084,1085

How can we stay away from BPA? A small amount of exposure comes from handling thermal paper, such as cash register receipts and printed tickets,1091 especially if our hands are greasy or wet after the application of lotion or sanitizer.

Ninety percent of exposure, however, appears to be from our diets.1093 How can you tell? When people fast for a couple of days, their BPA levels drop as much as tenfold.1094

the highest BPA levels have been found in canned green beans and canned tuna.

The only fresh food found contaminated with BPA in the United States was sliced turkey.1099

Take-Home Tip: BPA is why I specify in The How Not to Die Cookbook to choose beans and tomato products in jars, aseptic packaging (Tetra Paks), or BPA-free cans. Eden Foods, for example, has a line of BPA-free canned beans. You can also BYOB: Boil Your Own Beans. It’s cheaper, and they end up with a better texture. My favorite way is to use an electric pressure cooker (like an Instant Pot).

Phthalates are another class of plastics compounds associated with weight gain.

In 2015, when meat was officially classified as a “known carcinogen” or a “probable carcinogen” depending on whether or not it was processed, the focus was on substances generated during cooking, curing, or smoking, rather than on pollutant contamination.

Given this, we could just follow recommendations to keep cooking temperatures under 260°F, thereby avoiding broiling, roasting, pan-frying, or any other cooking method that causes a crust to form, and instead stick to boiling or microwaving to keep the outside “pale and soft.”1117 But even just being around a barbecue may be hazardous, based on the recognition that light clothing probably provides little protection from gaseous carcinogens.

Polycyclic aromatic hydrocarbons (PAHs), a class of combustion by-products found in cigarettes, car exhaust, and grilled meat,1119 may explain why the Long Island Breast Cancer Study Project found a 47 percent increase in breast cancer risk among postmenopausal women with a high lifetime intake of grilled, barbecued, or smoked meats.

Taking all thirty-three chemical pollutants in meat shown to be potentially carcinogenic into account, some European toxicologists suggest limiting children’s consumption of beef, pork, and chicken to no more than five servings a month, an average of no more than one serving every six days or so.

Our fat stores—like those of farm animals—harbor toxic pollutants. How do we know this? Because we see a surge in these chemicals in people’s bloodstreams as they lose weight.1144

The release of these compounds trapped in our body fat may then affect our metabolisms, slowing down the rate at which we burn calories during sleep, which could frustrate additional weight loss.1146

To help break this cycle, a reduction in animal fat is suggested to reduce further accumulation of pollutants, along with an increase in whole grains, as the fiber may help draw toxins out of the body.1147

Indeed, those choosing organic were better educated and better off financially, both of which in and of themselves have been associated with lower obesity risk,1153,1154 and, more to the point, exercised more and had better diets.

Those who chose organic ate more whole plant foods and less meat, dairy, and junk. No surprise they had a healthier weight.

Take-Home Tip: Personally, I try to choose organic whenever I have the option, but I never let pesticide concerns prevent me or my family from indulging in as many fruits and vegetables as possible regardless of how they were grown.

Ironically, one of the food components that produces the most dramatic effects is something that initially appeared to be the most inert of dietary constituents: fiber.1174

In fact, telling people to increase their intakes of fiber-rich foods may actually be one of the single most effective pieces of advice for weight loss.

Fiber seems so, well, boring. By definition, fiber is indigestible. Since it can’t be absorbed into the body, it just sta...

If just half the adult population ate three additional grams of fiber a day—only a quarter cup of beans or a bowl of oatmeal—we could relieve enough constipati...

But it’s not as if we thought fiber really did anything beyond helping to keep us regular.

While it’s true we can’t technically digest fiber, that’s only applicable to the part of us that’s actually human. But most of the cells in our bodies are bacteria.1176 Our gut flora, which weigh more than one of our kidneys and are more metabolically active than our livers,1177 have been called our “forgotten organ.”1178 And our good gut bacteria don’t just digest fiber—they thrive on it. Fiber is like comfort food for your colon. So we can digest fiber, just not without a little help from our little friends.

Fiber-rich foods require more chewing, slowing down eating rate, which itself can improve satiety.1188 This also allows for more secretion of saliva and stomach juices.

In one study, researchers spread a barium paste onto slices of different kinds of bread and found that, upon x-ray, the stomach shadow was larger after eating whole-wheat compared to white bread, showing how much fuller you physically get.1189

It’s Not the Calories You Eat but the Calories You Absorb

Our bodies can only absorb nutrients when they come in physical contact with our intestinal walls, so fiber, which never gets absorbed, can act as a carrier to dilute and even eliminate calories out the other end.

Fiber doesn’t just trap sugars; it can act as a fat-1193 and starch-blocker 1194 too.

Eat whole-grain bread as opposed to white bread, and stool analyses will find that you flush out nearly ten times as many carb calories.1197

It’s not what you eat but what you absorb, so you can lose more weight on a high-fiber diet eating the exact same number of calories simply because some of those calories get trapped and never make it into your system.

dietary fiber results in reduced caloric intake:1205 dilution of calories by expanding the volume of food, distention of the stomach through fluid absorption, delay in stomach emptying of the gelled mass, and dumping of calories by blocking the absorption of other macronutrients, such as carbs and fat. That fourth D triggers a fifth phenomenon known as the ileal brake.

psyllium is nonfermentable, meaning our gut bacteria can’t eat it—so although it can improve bowel regularity, it cannot be used to make the key ingredients for appetite suppression.1238 Eat fiber-rich foods, though, and our good gut flora take the fiber we eat and churn out molecules that calm our cravings.

literally by definition, fiber is only found in plants.1284 There is zero fiber in meat, dairy, or eggs and typically little or no fiber in junk food.

Nearly the entire U.S. population fails to eat enough whole plant foods—the only place fiber is naturally found in abundance.

fiber-rich foods listing an array of whole, unrefined plant foods.1292 Those of us who may be a little smug about our hearty intake of fruits and vegetables need to realize that fruits and leafy veggies are the poorest whole-food sources of fiber. Why? Because they’re 90 percent water. Root vegetables have about twice as much on a per-weight basis, but the fiber superstars are whole grains and legumes, which include dried or canned beans, split peas, chickpeas, and lentils.1293

Taken from the social psychology literature, the halo effect theory helps explain these types of leaps. Positive personality traits, for example, are inexplicably attributed to people who are more physically attractive.

The reason our bodies so easily store fat as fat is because it’s already fat. Our bodies can turn protein or carbs into fat, but it’s costly. To store one hundred calories of dietary fat as body fat, it only takes three calories of energy, but converting one hundred calories of dietary carbs into fat for storage takes twenty-three calories.

is why our bodies would rather burn carbs and store fat instead of the other way around. Simply stated, fat may be more fattening.1450 When we eat a meal, most of the fat is deposited directly as fat on our bodies, whereas a large proportion of the carbs get stored in our muscles for quick energy.

The researchers found that about 50 percent went straight into belly flab, 40 percent to their thighs, and most of the remaining went into visceral fat, the fat that’s buried around our major organs.

Normally, our bodies burn fat around the clock at, interestingly, about the rate at which a candle burns. (Candles, after all, used to be made from animal fat.1461)

Carbohydrates are the body’s preferred fuel, so when we eat them, our bodies switch from burning fat to burning carbs, effectively snuffing out the candle for a few hours. So, while we can certainly gain weight from eating carbs, it’s more from sparing our own fat from being used, rather than adding more fat directly.1462

if you switch people from a 38-percent-fat diet of mostly saturated fat to a 38-percent-fat diet of mostly monounsaturated fat, like that of a more Mediterranean diet, they also lose body fat.

The same number of calories and the same amount of fat—but a different type of fat—meant a different degree of weight loss.