A combination of factors makes a food fattening. First and foremost, the most fattening foods in our diet are those that we compulsively eat, and not all foods are like this. While many people may have found themselves mindlessly eating a quart of ice cream or a bag of M & M’s, have you ever heard of someone binge eating steak or grilled shrimp?I love a good porterhouse, but I’d be hard pressed to finish a 16 ounce serving. However a pint of most premium ice creams has about the same amount of calories. Yet somehow polishing that off doesn’t seem very hard.Besides taste, what causes some foods to be eaten compulsively while other foods can be eaten in moderation with little or no will power? The answer lies in the way foods affect the chemicals in our brains.Although all foods trigger the reward centers in our brains, some seem to affect it to a much greater extant than others.Quick digesting carbohydrates, particularly sugar of any type, are the biggest culprits. Researchers at Princeton found that rats fed sugar water have a large dopamine release in their brain. Drugs of abuse, such as cocaine and heroin, cause a release or an increase in dopamine levels in the same area of the brain. This would explain why many people find themselves almost unconsciously eating candies, cookies, and crackers even when they are no longer hungry.Another characteristic of fattening foods is their ability to raise insulin levels. Insulin is released by our bodies primarily when our blood sugar increases. Certain other foods, such as proteins (particularly those high in branched chain amino acids), artificial sweeteners, and possibly even dairy fat can also increase insulin levels in the body.I’ll spare you the biochemistry, but insulin makes us fat. Any Doctor who has ever treated a diabetic patient knows this. Treat someone with insulin and they immediately gain weight, even if they are already obese.In general, foods that increase your blood sugar the most, such as sugars and processed grains, cause the largest release of insulin.Finally, the most fattening foods are high in calories. This seems obvious but probably accounts for much of the difference between very similar foods. For example, a large glass of OJ has about 250 calories. We would need to eat four oranges to get the same amount of calories! Both oranges and orange juice taste good, they are both high in sugar, and they both cause a rapid increase in blood sugar. In fact, the glycemic index (a measure of how much a standard amount of a certain food increases your blood sugar) of oranges and orange juice are nearly the same. But oranges are inherently low in calories and orange juice in inherently high in calories.Many of us drink a large cup of OJ with breakfast. And most of us think this is healthy. But in reality, OJ has more calories and sugar per ounce than soda!Without further ado, here is my list of the eight most fattening foods.Eight Most Fattening Foods8) Salted nutsNuts are a fairly low carbohydrate food and they do not cause much of a blood sugar spike. But they are incredibly high in calories AND can be eaten compulsively. Varieties with added sugar, such as honey roasted peanuts or candies walnuts, are the most fattening but all varieties can cause problems.Although generally a healthy food, low in sugar and high in fiber and certain minerals, they should be avoided if you are trying to loss weight. One important note: raw, unsalted varieties don’t seem to cause overeating the same way as roasted, salted varieties. If you must have them around, try buying these types of nuts.7) CheeseThis is another low carb food that can be easily eaten to excess. There is also some research that shows dairy fat has a unique ability to stimulate an insulin release (most fats have no effect whatsoever on insulin release).Processed cheeses and those with mild flavors, such as cheddar, American cheese, and queso, seem to be the most fattening, but all varieties can cause problems.6) Any food labelled “Fat Free” or “Reduced Fat”Foods labelled “reduced fat” should really be labelled “increased sugar.” Almost inevitably when food processors remove fat they replace it with sugar or some other high glycemic index carbohydrate.One example of this is a Starbucks blueberry muffin. The low fat versions has 25 more grams of sugar and half the fiber of the regular muffin!So if it says “low fat” just avoid it!5) Potato chips and other salty snack foodsChips, crackers, and other salty snack foods are all fattening. They are all high in calories, cause a significant insulin release, and are often eaten compulsively. Even popular diets foods like baked potato chips and fat free pretzels should be avoided.4) Bread and other wheat products – Bread is another food that fits all three of my criteria for fattening foods. In addition, there is some research that suggests wheat may interfere with leptin signaling.*Leptin is a hormone that decreases appetite and increases energy expenditure. It is released by fat cells in direct proportion to the amount of body fat a person has. It is theorized that wheat can cause leptin sensitivity, thereby changing a persons body fat set point. This resulting leptin sensitivity literally “tricks” the body into thinking it has less fat storage than it really has. When leptin signaling is thrown off, appetite increases and energy expenditure decreases because the body is trying to gain fat!3) Breakfast cereals – Most breakfast cereals, even supposedly heart healthy ones like cheerios, spike blood sugar to extremely high levels. In fact, cheerios actually have a higher glycemic index than soda! And cereal is often eaten compulsively. How many of us have raided the pantry at night for a bowl of cereal? And how often does it end at just one bowl?Most people make this food even worse by adding raisins or bananas. Although considered by most to be healthy, a breakfast of cheerios and sliced bananas in skim milk with a glass of orange juice will insure a blood sugar roller coaster for the rest of the day. You’d be better off skipping breakfast than starting your day like that.2) Milk chocolate and other candy – Candy is loaded with calories and sugar. Most of us already know we need to avoid these foods if we are trying to loss weight. If you have an insatiable sweet tooth or your are a “chocoholic”, try eating only chocolate that is at least 75% cocoa. Also consider shaving it off with a sharp knife or potato slicer and letting the shavings dissolve on your tongue one or two at a time.1) Sweetened Beverages – Soda, sweet tea, and other sweetened beverages are the most fattening foods around. They are very quickly digested and cause a large insulin release. It takes only a few seconds to chug a 12 ounce can of soda, yet that beverage contains 150 calories! Consuming that many calories from solid food sources, even candy, would take much longer. Even 100% fruit juice contains an incredibly high amount of sugar and should be avoided if you are trying to lose weight or if you have metabolic syndrome, pre-diabetes, or diabetes.RecommendationsTo lose weight (or to avoid gaining weight) it is important that we reduce or eliminate these fattening foods from our diet. Sometimes, eliminating even one of these foods can cause a significant weight loss. One client I worked with lost 18 pounds in one month simply by cutting cheese out of her diet! It is also typical to see a double digit monthly weight loss by cutting out soda and all other caloric beverages. But it is not necessary to eliminate all of these foods completely.Some of the strategies I have found to be most helpful include:1) Start with breakfastMost typical American breakfasts are loaded with processed grains and sugar. Even a “healthy” breakfast of cereal with skim milk, juice, and dry whole grain toast will sky rocket your postprandial blood sugar and leave you hungry and low energy two or three hours later. Other typical choices, like muffins, doughnuts, and bagels are just as bad, although the fat in these foods can help to stabilize your blood sugar and keep you full for a little longer than the first example.Instead of the typical choices, start your day with a low carbohydrate, high protein, and high fat meal. Eat foods naturally low in carbohydrates such as eggs, avocados, olives, smoked salmon, and naturally cured breakfast meats. Small amounts of low calorie fruits such as raspberries or blackberries can also be included.2) Strive to eat halfIt can be very discouraging to imagine a life without your favorite foods. So don’t. Instead strive to eat half.Take half the bread off your sandwich. Eat half of the pasta that is served with your grilled chicken. And when you eat desserts, share them with a friend.3) Don’t keep fattening foods aroundMost people overeat at night. But if you don’t have fattening foods in your pantry you can’t eat them. Don’t buy candies, chips, cakes, or cookies. Ditto for breakfast cereals and breads. And I don’t accept the excuse that you need to have these foods in your house for your kids. Even if you feel that you have to keep some snack foods around for them, don’t buy ones that you like!4) Consider supplements and super foodsFenugreek and cinnamon extracts have both been shown to improve postprandial blood sugar spikes. Acidic foods such as vinegar and lemon juice can also lower blood sugar. Medium chain triglycerides (i.e. coconut oil) and green tea have both been shown to increase metabolic rate and energy expenditure. And fish oil seems to improve just about every condition known to man.