Over sixty years of research has shown that 95 – 98% of weight loss programs based on limiting calories and increasing activity do not work. Of the few who lose weight, over two-thirds will gain back more than they lost to begin with (Freeman, 2020).
Limiting calories has been all we have heard for years, so I understand the difficulty wrapping your head around this. But let’s examine this more.
According to the National Health and Nutrition Examination Survey (NHANES) completed in the US between 1990 and 2010 there was no association between calories and weight gain. Over that time, the average calorie consumption did not change, but obesity rates rose by 0.37% each year. (Fung, 2016, p32). Research shows that this increase in obesity may have more to do with the type of calories we eat versus the calorie count. Our lives have become convenient. We eat more snack foods, fast foods, or pre-packaged, highly processed foods instead of whole foods, and we eat all the time.
Limiting Calories Wreaks Havoc on Our Metabolism
Our body’s energy expenditure is dependent on the energy (calories) we put in our bodies. When we decrease calories (energy input), our bodies reduce the amount of energy output. Yes, this is your metabolism slowing down to accommodate for the reduction in fuel.
This is our body’s way of balancing. If you normally eat 1800 calories per day and begin eating 1500 calories per day, you will initially lose a little weight. But after a while, your body becomes accustomed to this lower amount of calories/energy and decreases its need for more energy. Your body begins to survive on 1500 calories, and weight loss comes to a standstill. When you begin eating your normal 1800 calories per day again, you gain weight back and probably a little more (Fung, 2016). Sound familiar?
Let’s Recap:
Calorie limiting weight loss programs rarely work.
What we eat may be more influential to weight gain and loss than the number of calories we eat.
Our body/metabolism adjusts when we decrease calories. Sustained reduction of calories = lower metabolism and lower energy expenditure.
From this information, we can deduce that simply decreasing calories does not work!
Now, please do not use this as an excuse to go eat all that ice cream in your freezer! Just because limiting calories does not work to lose weight, does not mean that eating a ton of extra calories from ice cream or candy won’t make you gain excess weight. It will!
If simply limiting calories is not an effective way to lose weight, how do we lose weight? There must be more to it! Let’s explore.
How Our Bodies Use the Fuel we Provide
First, it is important to understand a little more about how our bodies work. This is simplified, but the basics are this:
We eat food in the form of carbohydrates, fats, and protein. Since carbohydrates are our main source of cellular fuel, we are going to focus on carbohydrates (carbs).
Our body breaks down carbohydrates via the process of digestion into glucose (sugar) for immediate use to fuel our cells. Extra glucose is stored in the liver and muscles in the form of glycogen. The liver and muscle can only hold so much glycogen. So, once they are full, the remaining glucose is stored as fat in fat cells.
If we run out of glucose in the blood stream to feed our cells (this happens after we haven’t eaten for a while, when we sleep, or after prolonged exercise), the body uses the stored glycogen. Before our bodies will access fuel from fat cell storage, all the stored glycogen needs to be depleted. Most of us eat often enough that our bodies rarely need to access fuel/energy from fat cells.
What are Carbs?
Carbs, shortened for carbohydrates, are compounds found in all fruits, vegetables, grains (wheat, oat, etc.), legumes (beans), nuts, and all plant-based foods. Sugar is also a carb. The amount of carbohydrates in each of these foods varies, and each produces varying amounts of blood glucose during digestion.
How our Bodies Store Excess Fuel
Insulin is a hormone released from the pancreas when blood glucose (sugar) is elevated. This occurs when we eat and is highest when we eat carbs. Protein digestion causes a slight insulin elevation, and fat digestion causes a very minimal insulin elevation. But we will not be focusing on protein or fat right now. Let’s stick to carbs because carbs are the main source of food that our bodies break down into glucose and burn as fuel.
Insulin plays a key part in energy metabolism (how we use fuel). Insulin functions like a key that opens a door to our cells to allow glucose to enter the cell and be used for energy. Every cell in our body uses glucose for fuel. Insulin also moves excess glucose into fat cells for storage when there is too much glucose in the blood stream. But we know that this only happens once the liver and muscles are full of glycogen (see above).
It is a balanced system: We eat carbohydrates, and via the process of digestion carbs become glucose. Insulin is released by the pancreas, and our body uses the glucose to fuel our cells with the help of insulin (the key to the cell door). Our liver and muscles fill up with glycogen for easy access to more fuel for our body during times when we are not eating. Once glycogen stores are full, insulin moves extra glucose into our cells as fat (or fuel for a rainy day).
As this process occurs, insulin levels go from high, to manage the higher levels of glucose in the blood stream, to low, as less glucose is present.
How we Burn Fat Storage
In reverse, when there is no longer accessible glucose to fuel our cells, glycogen stored in the liver and muscle is easily converted back to glucose and released into the blood stream. If we use all the fuel from the stored glycogen, only then do our bodies begin to pull fuel from fat cells to burn as energy.
Insulin and its Relationship to Obesity
Insulin is needed for fat storage. Fasting insulin levels are about 20% higher in obese people (Fung, 2016, p78). There are many studies about diabetics that show the more injectable insulin a person with diabetes uses, the more weight they will gain. Now, this is a fine balance, because if a person with diabetes does not take insulin, their blood glucose levels can reach dangerously high levels which can cause a significant amount of damage to the body. Our bodies need insulin! However, more insulin = more fat storage and weight gain.
Why are Insulin Levels Higher in People with Obesity?
Insulin resistance. Have you heard of this? Similar, to how our bodies respond to drugs or alcohol, when we use these substances in excess, eventually we need more of it to feel it’s effect. We become resistant to the drug and require more of it for effectiveness.
Our body reacts to insulin in the same way. Many eat high carbohydrate meals three times a day. After every heavy carbohydrate meal or snack, our pancreas sends out more insulin to move the glucose from the blood stream into the cells. This results in constant high insulin levels.
After continued exposure to elevated levels of insulin, the receptors (the locks on our cell doors that allow the glucose in) become less affected by the insulin (the key). The insulin that opens the cell door to let glucose in quits working well. So, our pancreas produces more and more insulin to reduce the amount of glucose in the blood stream. It is a vicious cycle. More insulin creates increased resistance from the receptors on the cells, which causes the pancreas to produce more insulin, which eventually creates more resistance, and the cycle continues.
Interestingly, insulin resistance is also affected by genetics, this is why obesity runs in the family sometimes (Pei et al., 2022)!
What got us to this point?
Fifty years ago, we did not have an obesity epidemic. But how we eat over the last 50 years has changed a lot. Most of us eat three meals a day and many have snacks in-between. The standard American diet is full of processed foods and is extremely high in unhealthy carbohydrates. Few can say that they eat the recommended amount of fruit or vegetables each day. And many eat a significant amount of highly processed grain products found in breads, pastas, crackers, and cookies. All these things increase insulin levels. And if we eat these foods all day long, insulin levels remain high all day long. And we now know that this leads to insulin resistance.
The question is, “How do we break this cycle?”
Years of research are leading many to believe that weight gain or loss is based on more than just calories in and calories out. Research shows that weight loss or gain has just as much to do with hormones, like insulin, and the types of food we eat.
There are many factors that play a role in weight gain and weight loss that I am not addressing here. But since we know that just reducing calories does not work to lose weight, what are some other options?
And how do we stop the cycle of insulin resistance, that leads to increased insulin production and increased fat storage?
Some Solutions to Consider:
Reduce your sugar intake. Limit sugary beverages, candy, ice cream, and other high sugar sources. Read the labels of food you buy. Your body processes sugar quickly and eating these foods create high glucose and high insulin levels.
Stop eating white bread and pasta. Highly processed grain products are not much different than eating sugar. Switch to whole grain products. Our bodies process whole grains differently.
Eat more fruits and vegetables! These are full of fiber, vitamins, minerals, and antioxidants and that our bodies need for healthy survival. Fruit contains natural sugars too, but our bodies process whole fruits differently than plain sugar.
Eat more healthy fat. Avocados, olives, and nuts are great healthy fat sources! Remember, fats cause very minimal insulin increase. Fats also help you feel full.
Eat healthy proteins in moderation. Many plant sources contain lots of protein too. Some protein sources raise insulin levels more than others. Proteins also help you feel full.
Eat more fiber. Fiber comes from unrefined, whole, plant foods (fruit, vegetables, & whole grains). Fiber helps regulate how sugar is processed, it helps you feel full, and is needed for bowel health.
Stop snacking. Snacking all day long keeps your insulin levels high. Our bodies were designed for periods of fasting. Your stored glycogen and fat will keep your body fueled. This will reduce the constant high levels of insulin production that leads to insulin resistance.
Consider a healthy low carb diet (some call this a healthy keto-diet). But make sure to eat healthy fats and proteins, and don’t skip vegetables or lower carbohydrate fruits! Keto may be good for you if you do it in a healthy way, however some recent studies have suggested that keto diets may induce insulin resistance (Long et al., 2023). (Watch for a blog on this soon.)
Consider intermittent fasting. Don’t eat breakfast if you’re not hungry. Eat when you are hungry. Remember, our bodies are designed to provide plenty of fuel to our cells during times of fasting. Fasting does not affect metabolism the same way that reducing calories does. And most importantly, it allows our bodies to use up some of that fat storage! This strategy can also be effective in reducing insulin resistance (Tsitsou et al., 2022 & Wang et al., 2022). (Watch for a blog on this soon.)
Consider the ancient remedy of fasting. Fasting, more than anything else, may improve insulin resistance and have many other healing effects. It may be the key to sustained weight loss (Fung, 2016). (Watch for a blog on this soon.)
* Those who are on medications, especially medications for diabetes, should speak to their healthcare provider before fasting or making any major changes to their diet.
As you embark on your journey to health, keep in mind that there is not one plan that works for everyone.
Please watch my blog for more about fasting and other important information that may guide you down a path of better health.
References
Freeman, L. (2020). A matter of justice: “Fat” is not necessarily a bad word. The Hastings Center Report, 50(5), 11–16. https://doi.org/10.1002/hast.1180
Fung, J. (2016). The obesity code: Unlocking the secrets of weight loss. Greystone Books Ltd.
Long, F., Bhatti, M. R., Kellenberger, A., Sun, W., Modica, S., Höring, M., Liebisch, G., Krieger, J.-P., Wolfrum, C., & Challa, T. D. (2023). A low-carbohydrate diet induces hepatic insulin resistance and metabolic associated fatty liver disease in mice. Molecular Metabolism, 69. https://doi.org/10.1016/j.molmet.2023.101675
Pei, J., Wang, B., & Wang, D. (2022). Current studies on molecular mechanisms of insulin resistance. Journal of Diabetes Research, 2022, 1863429. https://doi.org/10.1155/2022/1863429
Tsitsou S, Zacharodimos N, Poulia K-A, Karatzi K, Dimitriadis G, Papakonstantinou E. Effects of time-restricted feeding and Ramadan fasting on body weight, body composition, glucose responses, and insulin resistance: A systematic review of randomized controlled trials. Nutrients, 14(22):4778. https://doi.org/10.3390/nu14224778
Wang, C., Zhang, X., Luo, L., Luo, Y., Yang, X., Ding, X., Wang, L., Le, H., Feldman, L. E. R., Men, X., Yan, C., Huang, W., Feng, Y., Liu, F., Yang, X. O., & Liu, M. (2022). Adipocyte-derived PGE2 is required for intermittent fasting-induced Treg proliferation and improvement of insulin sensitivity. JCI Insight, 7(5). https://doi.org/10.1172/jci.insight.153755
Great information, thank you:)