Conquer Cravings. Retrain Your Fat Cells. Lose Weight Permanently. The newly released best ­seller Always Hungry presents an updated analysis of the current science to help readers establish a solid foundation for long ­term weight management and overall health. It is an excellent supplement to the information contained in Why We Get Fat, by Gary Taubes.

Obesity researcher Dr. David Ludwig is a Pediatric Endocrinologist and Professor of Pediatrics at Harvard Medical School and a Professor of Nutrition at the Harvard School of Public Health. His work has been influential in advancing the science behind the theory that overeating does not make you fat; it is the process of getting fat that makes you overeat. The role of fat cells and what happens to them after years of high ­carbohydrate diets is central to his research and theories. He explains, as does Gary Taubes, how restricting calories slows metabolism, compounding the inability to permanently shed unwanted pounds. Starvation diets don’t last, and a very high percentage of such dieters end up weighing more than before the diet began. These calorie­ deficient diets often result in nutrient depletion, depression, and a feeling of failure.

The first third of Always Hungry concisely lays out the author’s conclusions drawn from 20 years of obesity research. Testimonials from several dozen patients who were part of the pilot program are also included. The remaining two ­thirds of Always Hungry is devoted to recipes and lifestyle changes to implement his program. Whole, natural, slow­ digesting foods are at the core of Ludwig’s approach to eating.

Because of its recent publication (Jan. 2016) and clear overview, topic points and summaries of the science sections’ findings are included below. At the outset, Dr. Ludwig acknowledges that the fallacy of calorie­ counting balance is not a new idea. In 1924, the Journal of American Medical Association editors wrote, “Although logic suggests that body fat may be decreased by altering the balance sheet through diminished intake, or increased output, or both….the problem is not really so simple and uncomplicated as it is pictured.”

BIOLOGY CONTROLS BODY WEIGHT

Our bodies like to stay in balance (called homeostasis); we have natural control systems and “set points.” When we cut calories our bodies fight to counteract the shortfall by slowing metabolism to conserve energy. And when we eat more, our metabolism speeds up. It is difficult to significantly change our body weight.

THE PURPOSE OF BODY FAT

Body fat, or “adipose tissue,” has a specific functions. It cushions our internal organs and protects us from the cold. Fat is also a fuel tank– ­­a calorie reserve that protects us from starvation and was key to our survival. Until recently in human history, our ancestors did not have a continual and steady supply of food, so had to rely on fat reserves during periods of shortage. Fat cells take up extra calories after a meal and release them as needed. Accessible carbohydrates are stored in the liver and accessible protein is stored in the muscle. But neither of these stores is as dense as fat stores because they are surrounded by a large amount of water (liver and muscle contain about 1/6 the amount of calories per pound as fat tissue). The human brain needs one out of every three calories we consume to stay alive.

HUNGRY FAT

Insulin: The Fat Cell Fertilizer­­— The main factor influencing fat cell behavior is the hormone insulin, which is made in the pancreas. It has the ability to lower blood sugar. Diabetes results from problems with the production of insulin. This hormone also impacts how all calories move throughout the body. For example, rats given insulin infusions ate more food and gained more weight than those that did not; even when their food was restricted, the rats still became fatter. Conversely, mice engineered to produce less insulin had healthy fat cells and burned more calories when given a diet that would have made a normal mouse fat.

Bottom line: Insulin drives fat cells to increase in number and size.
Query: What drives fat cells to produce too much insulin?
Answer: Carbohydrate (“specifically sugar and the highly processed starches that quickly digest into sugar”).

Our Fat Cells Make Us Overeat— ­­Basic endocrinology tells us that when our fat cells are programmed to grow, we overeat. High insulin levels “trigger” fat cells to hoard glucose and fatty acids. Insulin puts the fat in the fat cells but keeps keeps the calories from coming out, thus causing us to get hungrier earlier than if we hadn’t eaten high­carbohydrate food. Eating puts calories in the blood, but when our blood sugar is crashing we usually turn to fast-­acting sugar-­carbs. Thus the cycle continues, and over time weight gain occurs.

The Brain’s Emergency Alarm System­­– If we stay on a low-­calorie diet, accessible calories in the blood decrease, which can cause receptors in the brain to release stress hormones (like adrenaline and cortisol) into the blood to try and unlock calories stores in the liver and fat cells. If this stress reaction occurs frequently, metabolism slows down and losing weight becomes almost impossible.

Too Many Calories in the Body But Too Few in the Right Place— ­­Insulin causes too many calories to be stored in the fat cells leaving not enough in the blood. It programs fat cells into “calorie-­storage overdrive.” And as people compensate for not enough calories in the blood to take care of the caloric needs of the brain, they continually overeat.

All Breakfasts Are Not Created Equal­­– In the 1990s, the author published a controlled study on twelve adolescent boys who were fed breakfasts in a lab setting consisting of the identical number of calories but with different carbohydrate, fat, and protein compositions (group #1– ­­highly processed carbs in the form of instant oatmeal; group #2– ­­minimally processed carbohydrates– steel cut oats with same number of carbs as meal in group #1 only slower to digest; group #3­­– vegetable omelet with fruit that had fewer carbohydrates, no whole grains and more protein and fat). The same meal was fed to each of the three groups at lunch. Throughout the afternoon, all groups had free access to a variety of foods including cheese, fruit, cookies, and bread. Group # 1 ate approximately 1400 calories throughout the afternoon; group #2 ate 900 calories; and group #3 ate 750 calories. The results showed a 650 calorie consumption variance between group #1 and group #3 merely by substituting different forms of nutrients. Similar results have been achieved by other researchers in over a dozen published studies.

Your Brain on Fast­-Acting Carbs— ­­Functional MRIs have demonstrated that eating fast­acting processed carbs also stimulates part of the brain that is “ground-­zero” for reward, cravings, and addiction (the nucleus accumbens). But Dr. Ludwig points out that stimulation occurs because of the impact this form of carbohydrate has on metabolism, rather than on taste.

The Type of Calories You Eat Affects the Number You Burn­­­— In 2012, the author published the results of a ten-­month study that was conducted on 21 young adults. For the first 7 months, a controlled diet reduced the subjects’ weight by about 25 pounds each; at this point the diet was adjusted to stabilize the weight at the new lower level. Three different diets were then administered and metabolic rate was tracked. The diet breakdown was high carb (60%); moderate carb (40%); and low carb (10%). Participants burned about 325 calories more per day on the low-­carb compared to the high-­carb diet, and 150 calories more per day on the medium­-carb compared to the high-­carbohydrate diet.

Eating Fewer Calories Yet Gaining More Fat— ­­An eating regimen based on beans (slow­digesting starch) versus white potatoes (quickly-­digesting starch) was given to rats for 18 weeks while controlling calories so that both groups received identical numbers. At seven weeks the potato­-fed rats started eating less food, an indication their metabolism was slowing. At the end of the study the rats weighed exactly the same, but the potato-­fed rats had 70% more body fat than the bean-­fed rats. A recent study on humans measuring body fat on high-­carbohydrate low-­fat diets versus low­-carbohydrate diets was performed on several hundred subjects with a large waist size. Preliminary results showed that diets had different effects on fat content in the abdomen and other organs, “above and beyond weight loss.”

ANGRY FAT

Unlike other organs, fat has the ability to expand and store calories yet still maintain its normal functions, but only up to a point.

Chronic Inflammation— ­­Because fat tissue contains our most concentrated store of energy it is protected by a large number of infection­-fighting white blood cells. In obesity, the immune system can become persistently activated which may contribute to inflammation and injury and lead to chronic diseases associated with inflammation.

Insulin Resistance,Type 2 Diabetes, and Other Health Issues— ­­Even if body weight plateaus, insulin resistance can occur after years of increases in body fat when the fat cells can’t take up more calories. Excess calories then can build up in places like the liver and the muscle because they have nowhere else to go. “These abnormal fat deposits, called ectopic fat, worsen insulin resistance, setting the stage for the development of diabetes.”

THE FALLACY OF THE “EMPTY CALORIE”

“A fundamental problem with the calorie balance view of obesity is that it considers all calories alike, regardless of source, in some obviously awkward way. ” Is 100 calories of a pastry and a peach going to affect the body in the same way? According to Ludwig, to skirt this predicament, nutrition experts have grasped onto the theory of the “empty calorie”:

It’s not the sugar in and of itself in the pastry that is bad, it is the fact that
it fills us up and takes the place of other choices that are more nutritious.

Unfortunately, this is a prevalent view today– ­­even within the field of nutrition. Nutrients do matter, but foods with similar nutrients (e.g., calories or even grams of carbohydrates) can affect hormones and metabolism “in profoundly different ways, determining whether we store or burn calories, build fat or muscle, feel hungry or satisfied, struggle with weight or maintain a healthy weight effortlessly, and suffer from or avoid chronic inflammation.”

THE MAJOR NUTRIENTS­­ CARBOHYDRATE, PROTEIN, AND FAT

In order to run effectively, our bodies need a few ounces of protein to repair tissues and “run” biochemical reactions that drive metabolism. It needs a fraction of an ounce of fat (omega 3 and omega 6 fatty acids) for cell membranes. One nutrient we don’t need at all is carbohydrate (the Inuit survive on traditional diets that are almost exclusively land and sea animals). The body can actually procure all the fuel needed for our brains with protein and fat alone, although Dr. Ludwig is not advocating taking up a ketogenic diet. He just highlights that there is great flexibility in what we choose to eat.

Protein plays a major role in weight control with the release of the hormone, glucagon. It is the counterpart to insulin, and is also produced in the pancreas. But unlike insulin, it pulls fuel out of storage. “Protein in the right amounts counterbalances carbohydrates.”

LOW CARBOHYDRATE OR SLOW CARBOHYDRATE?

“Just as calories differ according to how they affect the body, so do carbohydrates. All carbohydrates break down into sugar, but the rate at which it occurs in the digestive tract varies tremendously… and forms the basis of the glycemic index (GI).”

The glycemic index ranks carb­ containing foods from 0­100, depending on how they affect blood glucose. One hundred is the GI number for glucose. Modern white potatoes, white bread, prepared breakfast cereals, and white rice, have a higher GI than table sugar (sucrose).

Ludwig also explains the concept of glycemic load (GL) ­­the carbohydrate content of foods as they are consumed. For example, watermelon and white potato are both high-­GI foods but watermelon does not have many carbs in a single serving, therefore its “load” is less.

Studies are cited to showing the success of low­-GI and low-­GL diets on body weight, and the potential corresponding effect on chronic diseases as indicated by observational analysis. High­-GI and high-­GL diets are referenced as being strongly associated with an increased risk for heart disease.

TYPES OF FAT

When a relationship between saturated fat and higher LDL cholesterol levels gained attention in the 1960s, nutritional guidelines began favoring low­fat, and in particular, low-­saturated fat diets as heart healthy. The following decade, margarine began appearing in refrigerators where butter use to be. This partially-­hydrogenated vegetable oil (known as a trans fat) proved to be far more dangerous than saturated fat. But in the last decade there has been a closer look taken at saturated fats and their role in cardiovascular disease. And although saturated fat may impact LDL cholesterol negatively, it also raises heart-­protective HDL cholesterol, and according to Dr. Ludwig, leaves the ratio of LDL to HDL unchanged.

Not all saturated fats are alike. Some studies indicate that dairy fat might be a healthier form of saturated fat. Also complicating matters is when carbohydrate and saturated fat is combined since carbohydrate influences how dietary fat affects blood lipids.

Dr. Ludwig’s position is that saturated fats are probably neither “public enemy #1, nor a health food.”

SUGAR AND ARTIFICIAL SWEETENERS

“Most sugars are composed of three basic building blocks­­glucose, fructose and galactose­­singly or combined in various ways.” Fructose has the sweetest taste of these three. Maple syrup, table sugar (sucrose), honey, and high­-fructose corn syrup, all contain about equal proportions of glucose and fructose.

High-­fructose sweeteners became popular in the 1970s as Americans were steered away from high-­fat foods. Unlike glucose, fructose is absorbed very quickly by the body. Too much fructose at one time can overwhelm the liver and lead to the production of new fat molecules. The fructose found in fruit, however, is contained within the cell walls and absorbs more slowly because of the fiber.

Artificial sweeteners (aspartame and sucralose) do not contain fructose or glucose but they still can affect the body. They can cause insulin secretions because of the artificial sweeteners’ impact on taste receptors and “drive” calories into the fat cells.

Dr. Ludwig recommends using honey or maple syrup when needing added sweetness due to their added nutrient and polyphenol content. Stevia leaf was not mentioned in the discussion of sweeteners.