It is often misunderstood. It’s one the most difficult physiological processes to achieve, and it’s probably why it’s so often misunderstood. Dubious weight-loss claims (Footloose eating breakfast will slow down your metabolism! ), and outlandish lies (apple cider vinegar speeds your metabolism up!).
The Mayo Clinic has a great definition of metabolism: “Metabolism refers to the way your body converts food and drinks into energy.”
Before we answer your burning questions about your weight, let’s find out what metabolism is.
There are four main components to your metabolism: BMR or Basal Metabolic Ratio; TEF or Thermic Effect Food; PA, Physical Activity Consumption; and NEAT which is Non-Exercise Activity Thermogenesis.
BMR + TEF +PA + NEAT = How many calories you consume in a day. This is what most people associate with their metabolism.
People who believe their metabolism is slow are saying that they don’t burn enough calories per day. People who can eat a pint of Haagen Dazs per day and not gain an ounce of weight are said to have a fast metabolism. But you’ll soon find out that this isn’t as easy as it seems. Is it possible that some people are blessed with a fast metabolism and others aren’t? In a moment, I will answer this question for you.
Let’s start with a quick science lesson from Mens Journal on how these four parts of metabolism function.
BMR refers to the number of calories your body needs for basic functions like heartbeat, temperature stability, brain functioning, and basically keeping you alive. The BMR is the largest consumer of calories. It can consume up to 60% (and sometimes even 80%) of total calories.
BMR represents a large portion of your daily calories. If you eat 1600 calories, nearly 1000 calories are going to be used in BMR. BMR may vary by as much as 15% depending on the person. We’ll explain why.
TEF refers to the number of calories your body needs to digest food. Every macronutrient, including carbohydrate, fat, and protein, has a different thermodynamic effect. Protein is the most energy-intensive macronutrient (roughly 20% of calories) and takes the longest time for your body to process. Fat is the least energy (around 5%). This is why high-protein diets are effective in weight loss. You’re using more energy to digest your food. You shouldn’t limit yourself to protein.
Thermic effects of food are generally believed to account for 10% to 15% of your daily calories. So, 160 calories from your 1600 calories will be used to calculate the TEF. These calculations are not a strict rule. They’re meant to illustrate the basic principles of how it works.
There are 440 calories left from 1600 you ate. Surprisingly, most of these calories will be used for non-exercise activity thermogenesis. NEAT refers to anything that isn’t exercise-related. For example, taking a shower, waiting in line at Starbucks, trying out clothes at Nordstrom (some people more vigorously than others), and so on. NEAT can contribute to a substantial amount of calories each day – as high as 2000 for some. For all non-athletes, actual exercise only accounts for a small portion of calories burned.
This chart says it all.
You can see how small the exercise (EAT). How large is your BMR? It’s crazy. This chart will help you remember that you can’t exercise if you eat a poor diet.
Now that you have an idea of how metabolism works and the main factors that influence it, let’s answer some of the most frequently asked questions about the subject.
What can I do to speed up my metabolism?
I can assure you that you will not be able to taste vinegar or cayenne pepper. I have reviewed many bogus metabolism boosters and fat burners that claim to ‘torch fat. It would be so simple!
Exercise is the only thing we know that can increase metabolism over time. Your resting metabolic rate (or BMR) will increase if you have more muscle mass. One pound of muscle will burn around 6 calories per day while at rest, while a pound worth of fat will only burn about 2. Although it’s not much, it can make a significant difference over the long term.
Strangely, eating a large meal can increase your TEF in the short term. You’ll burn more calories if you eat a large meal than you would if you had a smaller meal. If you do it enough, however, you will gain weight due to the increased calories.
What is the difference in BMR between individuals?
There are many reasons why this is so, but these are the most important:
Genetics. Genes play a major role in your life. BMR can also be influenced by genes, just as your dad’s eyes and mom’s skin.
Age. As our bodies age, we naturally lose muscle and slow down our metabolism. Boooo.
Sleep. Studies indicate that people who get less sleep may have a slower metabolism.
Hormones. __S.56__ Hormones will be a topic for another post.
Muscle mass. Like I mentioned before, the greater your BMR, the stronger you are. Some people are more skilled at building muscle than others. Men naturally have higher BMRs because they have more muscle. This is why my female clients are often frustrated when their husbands lose weight faster than they do. It’s frustrating, I know.
Your body’s size. More calories are required to live.
We suspect that gut bacteria may play a role in BMR. However, more science is needed to confirm this.
Why shouldn’t everyone eat a lot of protein, considering how protein is so efficient at burning calories.
A mixed diet makes life so much easier and provides nutrients that are not available from protein. A higher-protein diet with 40% carbs is my preference, as opposed to the recommended 60%.
Is it possible to go without breakfast and slow down my metabolism?
I am not convinced.
Some people have reported weight loss by eating breakfast. This is because breakfast-eaters are more likely to be active. However, there hasn’t been any convincing research on humans that would prove this. It seems that the amount of energy you consume over the course of the day is more important than the number of meals.
If you feel that eating breakfast helps you eat less later on in the day, or if it makes you hungry when you wake up, then eat breakfast. If you don’t eat breakfast and it doesn’t affect your food intake or your mental and physical activity throughout the day, then I would encourage you to keep doing what you are good at. Everyone is different.
Is spicy food good for my metabolism and helps me burn fat.
No. There has never been food or supplement that can increase metabolism sufficiently to make it possible to lose weight. There are no miracle cures.
Is it possible to gain weight by eating before going to bed?
Your metabolism is not the problem. It doesn’t matter if you eat too much at night.
Although our metabolism slows down a little during the night, it doesn’t stop (you would be dead if it did). This whole “don’t eat after 7 pm” thing is a way to prevent people from eating mindlessly after dinner. It’s not scientifically proven that food eaten after 7 pm can turn into fat.
Don’t go to bed hungry. This can have a negative impact on your sleep quality. Take a bite and don’t worry about it.
Intermittent fasting is a good way for your metabolism to increase?
Recent studies (some rodents included, though) showed promising metabolic effects from IF. However,’ speeding metabolism’ was not one of them. This case relates to hormones that are associated with fullness and hunger.
The 2018 study suggested that intermittent fasting may be preventive in slowing down metabolism. However, more research is needed to confirm this. In terms of weight loss, intermittent fasting does not appear to be an option over regular calorie-cutting. Hm. Hm. Personally, I would rather that you focus on the quality and nutrition of your food than how many calories you eat or don’t eat.
Are you able to burn significant calories by fidgeting or moving around a lot?
Yes. NEAT is responsible for the bulk of our non-resting energy needs. People who move more tend to be healthier. is a group of people who fidget. Fidgeting can be distracting so it is worth moving more.
How does diet affect my metabolism? Was it possible to ‘break’ my metabolism by dieting so often?
Our bodies are very smart and have been programmed to store fat. It may be due to the adaptations that we have had to make during times of hunger and thirst. Whatever the reason, fat loss can be made more difficult by our bodies when we eat.
Our bodies adapt to losing fat by dieting.
Hormones reduce our metabolism to conserve energy. They also increase our hunger to make us eat more.
Your metabolism may also be affected if you are losing muscle due to a low-calorie diet.
Your body needs less energy when you lose weight. This is the most difficult part of dieting. The theory goes that you will need less energy as your weight drops until you reach a diet calorie limit that is unsustainable.
Your metabolism doesn’t have to be ‘broken’ if you are a yo/yo dieter. This study shows that even yoyo dieters can lose weight, despite having experienced ‘weight cycling.
I was asked by a viewer about the Biggest Loser Effect. This is basically the phenomenon where participants in Biggest Loser TV shows lose a lot of weight quickly and then gain weight and have slowed their metabolisms. This is not normal yo-yo or normal dieting. These people lost up to a pound per week. Extreme weight loss over a short period of time can certainly alter your metabolism. However, this isn’t normal behavior for most people, and more research is needed to address this issue.
You can lose weight while not affecting your metabolism. To do this, you should build muscle mass by exercising and eat a higher protein diet. Instead of focusing on reducing calories, you can eat more whole foods or minimally processed foods, and eliminate crappy, refined, ultra-processed junk food.
Do I have a predetermined metabolism and can I stick with it?
No! Genes are only one part of metabolism. Remember that metabolism can be improved by increasing muscle mass, moving more (increasing NEAT), and eating more proteins.
Do I need to ‘graze’ in order to maintain my metabolism high throughout the day?
This is a myth. Some people may eat more if they eat less often. There is no way to lose weight by eating less or more often. Do what works for you. However, there is no evidence that 6 meals a day will increase your metabolism.