Monday, August 20, 2018

Food and Dieting Myths - Healthy weight loss

In trying to maintain a healthy weight I needed to unlearn many of the myths surrounding food and dieting.


I used to believe that the number of calories I ate were the key to weight gain. I believed the myth that calories in and calories out accounted for all weight changes. This was very frustrating for me because I just couldn’t seem to eat small enough portions to lose weight. Also, eating these small portions left me very hungry and unsatisfied.

Eventually a doctor I consulted recommended a low carbohydrate diet and suddenly I started to shed my excess weight without difficulty. What I came to learn is that contrary to popular belief, calories are NOT the only thing you need to concern yourself with when it comes to losing weight. Research over the last 20 years has made remarkable progress in understanding adipose tissue (body fat cells) and how we gain and lose weight. Calories have very little to do with this process. Some calories (carbohydrates and sugar) can turn straight to excess body fat and some simply cannot.


We’ve probably all heard the saying “you are what you eat,” but that doesn’t mean that when we eat fat, we get fat. This is perhaps one of the biggest and most misunderstood aspects of diet. The most important lesson about fat and dieting is that without sugar or carbohydrates, even a diet that is high in fat simply CANNOT make you gain weight.

In fact, there are many benefits to eating fat for weight loss. Not only is fat necessary to the flavor of food, it also leads to feeling satiated and full after a meal. Obviously, it is much easier to lose weight if you feel satisfied after meals.

As evidence that eating less fat does not lead to weight loss, in the last 50 years or so, dietary fat consumption has been reduced dramatically in the United States while carbohydrate (especially sugar) consumption has skyrocketed. If a low-fat diet really helped with weight loss, then we should have seen a reduction in obesity rates. In fact, we see the exact opposite...a massive unprecedented increase in obesity, insulin resistance, and diabetes.


The fat that forms in your body has very little to do with the fat that you eat, but a lot to do with how much glucose that you eat from sugar and carbohydrates. When you eat carbohydrates, it is broken down into glucose. Some of this glucose will be used immediately for energy but any excess will be joined with the fatty acids from the fat that you eat to create fat cells. Body fat is simply a way for your body to store excess glucose so that it can be used later (e.g. during sleep or times of famine).  

The mechanism for this is that carbohydrates trigger insulin to be released. Insulin then binds excess glucose from carbohydrates to fatty acids, turning this combination into fat cells. The key here is that fatty acids (from “fat” in food) alone DO NOT get stored as body fat. In fact, in the absence of carbohydrates, any excess fat is simply flushed out in our stool.


A very important thing to understand is that eating healthy fat is critical to everyone’s health. When we eat fat, it breaks down into fatty acids which are then absorbed into our body. Some of these fatty acids are “essential”, meaning that we can only get them from our diet and our body cannot make them in any other way. Essential fatty acids are used throughout our bodies for many purposes (including brain function).

Also, in the absence of glucose in our bloodstream, fatty acids are used to create energy for muscles and many other body systems. Low fat or non-fat diets are not only virtually meaningless for weight loss, but they can also be dangerous in the long term as you are deprived of essential fatty acids that are critical to every system in your body.


Another thing to consider in trying to lose weight is that different sources of calories require very different amounts of energy in your digestive system to fully break them down. Protein takes a lot more energy (both heat and chemical energy) to break down and a relatively large amount of time to absorb in the gut than does sugar. Sugar/carbohydrates break down to glucose and is absorbed pretty much “as is”, providing a large amount of energy at almost no digestive cost (since almost every cell can use glucose directly for energy). Fats take even longer to digest than protein or sugar. If you want to lose weight, you want to make the body work for its calories. Fat and protein are the best choices, while carbs are not.


Eating some carbs are essential to good health. For example, vegetables and fruit are carbohydrates. There are many healthy molecules in fruits and vegetables that contribute to overall health.

The key for weight loss is to eat the carbohydrates that have the lowest ability to raise glucose levels (the lowest glycemic index). This includes foods that are the least sweet, for example green vegetables.

I like to explain that the foods that will turn into a new plant (grains, legumes and tubers like potatoes) have the greatest density of carbohydrates stored as energy to create a new plant. However, foods like green vegetables have already expended this energy and so have a lower carbohydrate content.

To lose weight, eat the carbs that have the lowest glycemic index. Foods that have a low glycemic index raise insulin far less than foods that have a high glycemic index. This prevents weight gain and obesity.


As we discussed, carbohydrates (a.k.a. sugar) get turned into fat pretty easily when eaten in excess. So, regulating carbohydrate intake is the best way you can control levels of body fat. If you were to eat almost no carbohydrates, your body would use up its stores of sugar (glucose and glycogen) pretty quickly and start to dip into its fat reserves for energy. Fat is then “burned” (split apart) for the sugar locked inside and used as the primary source of energy.

The brain uses glucose when it is available, but once that runs out, it switches to using protein for energy by making and using molecules called “ketones”. So, in the absence of carbohydrates (and sugar), your body will simply use fat and protein for energy. There is nothing wrong with this, and our ancestors ate diets rich in protein and fat (from animals) before (and after) the invention of agriculture.

Finally, if you suffer from cravings for carbohydrates and sweet things, the best way to end the cravings is to eliminate all carbs from your diet for about 3-5 days. Your body will switch its metabolism over to using ketones and fat, and your carb cravings will start to resolve.


Getting the right ratios of protein, fat, and carbohydrates in your diet goes a long way toward reaching and maintaining weight goals. Since the levels of carbohydrates necessary for weight control vary between individuals, there is no real blanket recommendation I can make other than to “eat fewer grams of carbs for weight loss” and “increase slowly to find a level of weight maintenance”.  Don’t be afraid of eating fat; remember, it won’t make you gain weight.


It bears repeating again that the amount of fat you eat has absolutely no bearing on the storage of fat in your body. Fat is a healthy part of our diet and provides us with the fatty acids we require to maintain health and vitality. In the absence of carbohydrates, our bodies use the glucose stored in fat cells (and then the fatty acids stored with it) as energy and you lose weight by “burning” body fat which ultimately leads to weight loss. A healthy diet incorporates the right proportion of protein, fat and carbohydrates that reverses obesity and helps maintain a healthy weight.

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