What Really Makes You Fat?

By Carol Chuang, MS, CNS, CHC, CMTA

Conventional nutrition advice says eating fat will make you fat. In order to prevent weight gain and stay healthy, you should eat a low-fat diet. This school of thought is fully embraced by many nutritionists, dietitians, personal trainers, doctors, and even our government agencies.

The truth is that there is no evidence that healthy fats are bad for you, as a matter of fact, they are essential for your body functions. Eating foods high in healthy fats doesn't mean that you will get fat. 

Weight gain/loss is not just about the calories because all calories are not created equal. Well, in terms of the energy in the calories, yes. But in terms of the fate of the nutrient (protein, fat, or carbs) downstream, the same amount of calories of different nutrients produces dramatically different effects.

It wasn't until the last 30-40 years that Americans have become so fat phobic and eaten so much low-fat and fat-free foods, yet Americans are getting fatter and heavier. Why? What does research say about the mechanism behind weight gain? What can we do to lose the fat?

Changes In The American Diet

In the last few decades, the American diet has gone through dramatic changes. Americans now eat less home-cooked meals but more processed foods, fast foods, and restaurant meals. The American diet consists of considerably greater amounts of grains and sugars, in particular, those derived from corn.

• Consumption of grain-based products (wheat, rice, corn, oats) went up 45% from 1970 to 2000, with most of it being refined grain.
• Consumption of sweeteners increased 23% during the same period, of which corn sweeteners (high fructose corn syrup, glucose, dextrose) surged 224%!

If you look at what Americans have been eating, these statistics are hardly a surprise. We are eating increasingly bigger bagels, muffins, doughnuts, scones, ice cream cones, pretzels, cookies, pizzas, wraps, and slices of bread. Restaurants appear to give better value for your money by serving humongous portions of pasta and rice, and unlimited quantities of bread, just because flour and rice are cheap. (Corn, cotton, wheat, rice, and soybeans are the five most heavily subsidized crops in the U.S.)

We are eating more sugar because food manufacturers have turned to sugar as the number one food additive. With the advent of low-fat and fat-free foods, manufacturers started adding sugar to compensate for the lack of flavor from the fat. These days, you may find sugar in the most unlikely places, such as peanut butter, mayonnaise, salad dressings, ketchup, spaghetti sauce, soup, boxed mixed rice, hot dogs, luncheon meats, canned vegetables, bread, pizza, and crackers.

We are also consuming more sugar and high fructose corn syrup-sweetened beverages, including soft drinks, fruit-flavored drinks, and enhanced waters. These days children don't even like to drink water because it has no flavor. 

Consequently, such dramatic transformations in our diet are being reflected in changes in our physique.

• Nowadays, the average American is a whopping 25 pounds heavier than 40 years ago.
• About 34% of adult Americans are overweight and 34% are obese. 
• About 17% of children and adolescents (2-19) are obese.

Excess Carbs Lead To Weight Gain

We all know that eating too much sugar is bad for our health; it leads to weight gain, obesity, and diabetes. But what about grains, especially whole grains, the so-called "good" carbs which are supposed to be wholesome and fat-free?

The truth is that grains, no matter whether they are refined or whole, are carbohydrates that eventually break down to simple sugars like glucose. Eating foods high in sugar, including starchy foods and grains results in a rise in blood glucose. The pancreas responses by secreting the hormone insulin, signaling cells in the liver, muscles, and fat tissues to take up excess glucose from the blood. Then, insulin tells the body to store fat and stop using it as an energy source.

Hence, if you are always eating sugar and a lot of grains, your body is constantly producing insulin to counteract the rise in blood sugar from the carbs. As a result, you are also changing the way the body regulates fat storage. Overtime, you will accumulate more fat and gain weight.

Weight Gain Is More Than Just Calories

Research finds that if you eat the same amount of calories from carbs, or carbs and protein, or carbs and fat, or protein and fat, you are going to have entirely different metabolic fates. And that metabolic fate is going to determine the hormonal response that regulates, among other things, how much fat you accumulate.

Protein and fat have minimal effect on the hormone insulin. In fact, eating healthy fats as part of your meal is conducive to weight loss as the fats slow down your food absorption so that you can go longer without feeling hungry.

Carbs, on the other hand, triggers the secretion of insulin, which tells your body to store fat and stop using it as an energy source. Thus, you can say that eating too much carbs will eventually make you fat.

Confusion About Fructose And The Glycemic Index

The glycemic index ranks carbohydrates according to their effect on our blood sugar levels. It uses a scale of 0 to 100, with higher values given to carbs that cause the most rapid rise in blood sugar. As a reference point, pure glucose is 100 on the scale; refined white sugar (half glucose-half fructose) is 65.

Fructose doesn't trigger a rapid rise in blood sugar and has the lowest glycemic index (19) of all natural sugars. This leads to its skyrocketed popularity in the last 30 years.

• In the 1980s, the American Diabetes Association started recommending its use by diabetics due to its small effect on blood glucose levels.
• Corn refiners pounced on this opportunity and came up with high fructose corn syrup (55% fructose, 45% glucose), which was marketed as a healthier sweetener than sugar. It's widely used in processed foods, baked goods, and sweetened beverages.
• Again, in the last 10 years, agave nectar producers jumped on the same bandwagon and claimed that agave is a healthy sweetener because it's 75-90% fructose and has a very low glycemic index (20-30). You can find agave in many supposedly "healthy" cookies, energy bars, and desserts.

There has been much debate about whether fructose contributes to the obesity epidemic in the U.S. After years of research, studies found that excessive fructose is far worse than glucose and other kinds of carbs! The reason is that fructose has its unique metabolic pathway.

1. When you eat glucose, it enters the bloodstream and your body releases insulin to help regulate it. When you eat fructose, it has to be processed by the liver. If the liver cannot process it all fast enough for the body to use as sugar, it is converted to fat and stored in the liver or sent off to the bloodstream as triglycerides. 
2. Fructose bypasses some of the important steps involved in satiety, such as the secretion of the satiety hormone leptin and suppression of the hunger hormone ghrelin. This is why a high fructose intake is likely to result in overeating and weight gain.
3. Excess fructose consumption may eventually lead to insulin resistance.
4. Fructose is eight times more likely than glucose in its contribution to glycation, a process by which sugars attach to proteins in the body, altering their structure and resulting in dysfunction of the cells. Glycation is associated with chronic inflammation, aging, cataract formation, diabetes complications, and cardiovascular problems.

Therefore, if you have any of the following conditions, you should significantly reduce your intake of grain carbs and sugar, in particular, fructose:

• overweight
• obesity
• diabetes
• insulin resistance
• non-alcoholic fatty liver
• high triglycerides
• high LDL ("bad") cholesterol
• high cholesterol
• high blood pressure
• high uric acid
• heart disease

Tips For Losing Fat

• To lose weight in the long-run, you need to adjust your eating habits permanently and adopt a new, healthier lifestyle. When people go on a "diet", they tend to severely cut calories, restrict food intake even if they are hungry, skip breakfast, eat lots of salads, and shuns virtually any food that's high in fat. Such short-term sacrifice may yield result but once they are off the "diet", most people eventually regain the weight.
• A truly healthy diet is one that's satisfying and energizing, or else you can't do it in the long-run. You should feel completely satiated after a meal and you don't have the desire for anything else, including sweets. Very often, you won't even need to snack until the next meal.
• Eating the right type of calories is crucial to successful weight loss. Counting calories alone is not enough because calories from different nutrients (protein, fat, and carbs) have different effects on your hormonal response that regulates fat storage. Depending on your body type, some people may have a higher tolerance for carbs. However, excess calories from sugar (especially fructose) and grain carbs will signal the body to store fat and stop using it as an energy source.
• Be aware that fruits are high in fructose. If you drink fruit juice, ounce for ounce, you are taking in as much sugar as sodas. Also, watch out for high fructose corn syrup and agave nectar in processed foods, cookies, energy bars, desserts, and sweetened beverages.
• Replace excess carbs with vegetables, proteins, and healthy fats. These nutrients have minimal effect on your insulin, which promotes fat storage.
• Eating healthy fats is conducive to weight loss as they slow down your food absorption and keep you feeling satiated longer. Examples of healthy fats include coconut oil, olive oil, avocados, raw nuts and seeds, fats from grass-fed animals, and their full-fat dairy products (butter, cheese, milk, yogurt).
• Exercise is important for weight loss, in particular, the right type of exercise. Doing regular aerobic cardio is good but if you want to substantially boost your metabolism and increase fat burning, engaging in 2-3 times of high intensity interval training every week is the most effective. Additionally, strength training is important for weight loss because it helps change your body composition by gaining lean muscles and losing fat. Exercise helps the cells in your body regain insulin sensitivity. With less circulating insulin, your body will be storing less fat.
• Make sure you get 7-8 hours of quality sleep every night. Chronic sleep deficit often results in weight gain. The two hormones that are key in this process are ghrelin and leptin. Ghrelin is the hormone that tells you to eat, and when you are sleep-deprived, your body produces more ghrelin. Leptin is the hormone that tells you to stop eating, and when you are sleep deprived, your body has less leptin. More ghrelin plus less leptin equals to weight gain.

© 2012 Carol Chuang

About the Author

Carol Chuang earned a Master of Science degree in Nutrition from Huntington College of Health Sciences. She is a Certified Nutrition Specialist from the American College of Nutrition, a Certified Health Counselor from the Institute for Integrative Nutrition, a Certified Metabolic Typing Advisor, and a Certified Functional Diagnostic Nutritionist. She is also board certified by the American Association of Drugless Practitioners.

Carol is a Professional Member of the American College of Nutrition and the Price-Pottenger Nutrition Foundation. Apart from having her private practice counseling individual clients, she writes a monthly nutrition newsletter, and conducts regular seminars on various topics of nutrition and wellness.