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A long debated topic amongst nutrition experts is whether or not a calorie really is just a calorie. Within the dietetics and medical community, most practitioners will tell you that yes, weight loss and weight gain are governed by the first law of thermodynamics, which states that the change in the internal energy of a closed system is equal to the amount of heat supplied to the system, minus the amount of work done by the system on its surroundings. As a result, most weight loss models have been built around this seemingly logical equation of energy in = energy out. Translation: if you take it in you have to burn it or it will be stored and we all know what excess energy get stored as - FAT. But is this really true?
To be honest, I am increasingly skeptical. Now, I do think that you can lose weight eating anything, and I mean anything, as long as the amount of calories that you are taking in is less than what your metabolism requires. This was clearly demonstrated by one of my professors at Kansas State when he lost 30 pounds eating Twinkies and other vile Hostess snack products. The key was, that he kept his caloric intake at or below 1,800 calories/day. In this case, the body is simply using its fat stores to address an energy deficit, which is ultimately the purpose of those stores: to get us through times of “famine” or low energy intake.
But what about how the body processes the different macronutrients, particularly carbs and protein? I am not going to argue that the calories in 1g of protein are different from the amount in 1g of CHO; both contain 4 kcals (calories). However, our hormonal responses to both are quite different, and those varying responses are key to energy balance.
While both carbohydrates and protein cause a rise in insulin, we know that carbohydrates are the main driver of this critical hormone. So lets examine the role of insulin in the body. Its primary function is to drive blood sugar into cells. This is a good thing because we don’t want a bunch of excess glucose floating around and wreaking havoc throughout the body, a condition called type II diabetes. At the same time, as insulin moves glucose out of the blood stream, it also prevents the breakdown of triglycerides (aka fat) by inhibiting another hormone called glucagon. So rather than breaking down fat, it drives fat storage.
Perhaps more importantly to weight loss or gain are the differing impacts these two macronutrients have on hunger and satiety levels. There are plenty of studies out there to demonstrate that protein is far more satiating than carbohydrates. So if you have a high protein lunch, you will probably be less likely to reach for a snack before dinner than had you had a high carb lunch. It should also be mentioned that if you have not yet jumped on the whole grain bandwagon and are still eating Wonderbread then you are sabotaging your weight loss efforts. Refined carbs are the worst choice as they have been shown to stimulate appetite and lead to overeating. Beware the delectable pastry!
Another factor that plays into our hormones and body response mechanisms is time of day. For instance, we know that our cortisol levels are highest upon rising in the morning and lowest before going to bed at night. Cortisol is an important stress hormone that has many effects throughout the body including counteracting the actions of insulin. But rather than delving further into a very complex topic, I want to take this opportunity to bridge over to the study that inspired this post.
The study was just published at the end of last month in the International Journal of Obesity. The researchers looked at the diets of 400 Spaniards undergoing a 20-week weight loss program and monitored their progress. They found that those eating their main meal before 3pm lost 25% more weight than those reserving their main meal for dinnertime. Both groups consumed about the same amount of calories; therefore, this strongly suggests that meal timing does play a role in whether we burn or store energy. In addition, late eaters exhibited reduced insulin sensitivity, which you already know is a major risk factor for Type II diabetes.
I thought these findings were incredibly interesting since many experts claim that meal timing does not matter. If a calorie was really just a calorie, then this assertion would be true, but this study certainly suggests that the widely accepted energy equation is flawed. So how can you apply this information to improve your weight loss efforts? Below I have listed a couple of tips.
1. Eat your main meal before 3pm. This does not mean that you can’t have dinner, but keep it light. So think lunch foods for dinner (soup and salad) and dinner foods for lunch (grilled chicken, brown rice and vegetables). Or do as the Spanish do and nibble on healthy tapas for dinner like steamed mussels, marinated sardines, and gazpacho.
2. Avoid high carbohydrate meals and shun refined carbohydrates. Now, please don’t go all Atkins on me, but do try to get your carbs low glycemic fruits, vegetables, and moderate portions of whole grains.
3. Get a good night’s sleep to keep appetite hormone levels in check. Sleep deprivation is really not your friend as it will get you on two fronts. First, it causes an increase in ghrelin, a hormone that stimulates hunger. Secondly, it causes a decrease in leptin, a hormone that sends satiety signals to the brain. This is a bad combination if you are watching your weight.
4. Manage your stress levels. Stress stimulates stress hormone production, which ultimately stimulates appetite. Your body thinks it needs to replenish energy stores when it actually doesn’t. Meditate, read, do whatever makes you feel happy and free.
Resources
International Journal of Obesity , (29 January 2013) | doi:10.1038/ijo.2012.229
To be honest, I am increasingly skeptical. Now, I do think that you can lose weight eating anything, and I mean anything, as long as the amount of calories that you are taking in is less than what your metabolism requires. This was clearly demonstrated by one of my professors at Kansas State when he lost 30 pounds eating Twinkies and other vile Hostess snack products. The key was, that he kept his caloric intake at or below 1,800 calories/day. In this case, the body is simply using its fat stores to address an energy deficit, which is ultimately the purpose of those stores: to get us through times of “famine” or low energy intake.
But what about how the body processes the different macronutrients, particularly carbs and protein? I am not going to argue that the calories in 1g of protein are different from the amount in 1g of CHO; both contain 4 kcals (calories). However, our hormonal responses to both are quite different, and those varying responses are key to energy balance.
While both carbohydrates and protein cause a rise in insulin, we know that carbohydrates are the main driver of this critical hormone. So lets examine the role of insulin in the body. Its primary function is to drive blood sugar into cells. This is a good thing because we don’t want a bunch of excess glucose floating around and wreaking havoc throughout the body, a condition called type II diabetes. At the same time, as insulin moves glucose out of the blood stream, it also prevents the breakdown of triglycerides (aka fat) by inhibiting another hormone called glucagon. So rather than breaking down fat, it drives fat storage.
Perhaps more importantly to weight loss or gain are the differing impacts these two macronutrients have on hunger and satiety levels. There are plenty of studies out there to demonstrate that protein is far more satiating than carbohydrates. So if you have a high protein lunch, you will probably be less likely to reach for a snack before dinner than had you had a high carb lunch. It should also be mentioned that if you have not yet jumped on the whole grain bandwagon and are still eating Wonderbread then you are sabotaging your weight loss efforts. Refined carbs are the worst choice as they have been shown to stimulate appetite and lead to overeating. Beware the delectable pastry!
Another factor that plays into our hormones and body response mechanisms is time of day. For instance, we know that our cortisol levels are highest upon rising in the morning and lowest before going to bed at night. Cortisol is an important stress hormone that has many effects throughout the body including counteracting the actions of insulin. But rather than delving further into a very complex topic, I want to take this opportunity to bridge over to the study that inspired this post.
The study was just published at the end of last month in the International Journal of Obesity. The researchers looked at the diets of 400 Spaniards undergoing a 20-week weight loss program and monitored their progress. They found that those eating their main meal before 3pm lost 25% more weight than those reserving their main meal for dinnertime. Both groups consumed about the same amount of calories; therefore, this strongly suggests that meal timing does play a role in whether we burn or store energy. In addition, late eaters exhibited reduced insulin sensitivity, which you already know is a major risk factor for Type II diabetes.
I thought these findings were incredibly interesting since many experts claim that meal timing does not matter. If a calorie was really just a calorie, then this assertion would be true, but this study certainly suggests that the widely accepted energy equation is flawed. So how can you apply this information to improve your weight loss efforts? Below I have listed a couple of tips.
1. Eat your main meal before 3pm. This does not mean that you can’t have dinner, but keep it light. So think lunch foods for dinner (soup and salad) and dinner foods for lunch (grilled chicken, brown rice and vegetables). Or do as the Spanish do and nibble on healthy tapas for dinner like steamed mussels, marinated sardines, and gazpacho.
2. Avoid high carbohydrate meals and shun refined carbohydrates. Now, please don’t go all Atkins on me, but do try to get your carbs low glycemic fruits, vegetables, and moderate portions of whole grains.
3. Get a good night’s sleep to keep appetite hormone levels in check. Sleep deprivation is really not your friend as it will get you on two fronts. First, it causes an increase in ghrelin, a hormone that stimulates hunger. Secondly, it causes a decrease in leptin, a hormone that sends satiety signals to the brain. This is a bad combination if you are watching your weight.
4. Manage your stress levels. Stress stimulates stress hormone production, which ultimately stimulates appetite. Your body thinks it needs to replenish energy stores when it actually doesn’t. Meditate, read, do whatever makes you feel happy and free.
Resources
International Journal of Obesity , (29 January 2013) | doi:10.1038/ijo.2012.229