Have you got a slow metabolism, and what can you do about it?
“I think I have a slow metabolism”.
Have you ever thought this?
Could be the reason that your weight loss seems impossible?
It’s true, your metabolic rate (how many kcals you burn during the day) will impact weight loss, however, before jumping to any conclusions it’s important to understand the parts that effect your total energy expenditure (TEE), or the number of kcals you burn during the day.
If you don’t understand these key elements:
1. You maybe overeating without even knowing it
2. You may overestimate how many kcals you burn through exercise
3. You may forget the fundamentals of what works when it comes to fat loss
If you do learn about what drives your metabolism:
1. You’ll be armed with the tools to understand how much you should be eating
2. Reaching your goals will be a lot easier
3. You won’t waste your money and stupid fat burner pills
OK, so what determines how many kcals you burn during the day? (TEE)
Your TEE is calculated by combining three elements of energy usage: the basal metabolic rate (BMR), the thermic effect of activity (TEA), and the thermic effect of food (TEF).
TEE = BMR + TEA + TEF
Your basal metabolic rate (BMR) is the energy your body requires to carry out the fundamental tasks of staying alive. This includes energy for your brain, your organs (breathing, keeping the heart and lungs functioning) and your muscles.
Your weight, muscle mass, age, gender and genetics impact your BMR, where larger individuals have higher energy (kcal) needs (even from fat mass).
Muscle requires more energy than body fat, although the actual increase in kcals used by a kg of muscle compared to a kg of fat is only a little higher - 13kcals.kg.day vs fat 4.5kcals.kg.day (1). That said, the ability to move more weight (increased strength), storage capacity (carbohydrates store in the muscle) and increased kcal burn from repairing muscle provides added benefits aside from just the small increase in your metabolism .
How to calculate your BMR?
You can use a simple equation to work out your BMR such ‘Mifflin-St Jeer’, ‘Harris-Benedict’ or the ‘Katch-McArdle’ method (Just google them). As these methods are based on averages, they may not be entirely accurate (calculations don’t adjust for individual differences).
The only way to be entirely accurately is through indirect calorimetry, which helps measure your kcal burn through gas analysis.
If you wanted to measure your metabolism, you can book a Resting Metabolism Test (RMR), where we are able to accurately gauge how many kcals you should be eating and prescribe you with an accurate nutrition plan.
Using our VO2max test, we can also see how efficient you are at burning kcals during exercise. This gives insight into how well your lungs, heart and muscles are working (also a strong predictor of health and longevity).
Interested to learn more? Click here to book your testing today: www.boxnutrition.co.uk/metabolic-testing
2. Thermic effect of activity (TEA)
The second component of your energy expenditure is the thermic effect of activity. This is the kcals needed for planned activity such as working out and non-exercise activity thermogenesis (NEAT). As you would assume, this can vary considerably between people based on how much they exercise. However, NEAT can also vary a lot between people. In fact this can differ by up to 2000kcals between people of a similar size!! (3).
3. Thermic effect of feeding (TEF)
When you eat food, your body requires kcals to break it down, digest and absorb it. This process is known as the thermic effect of feeding (TEF). Of your total energy expenditure, this accounts for around 5-10%, however the composition (protein, carbs and fat) of your meal can significantly affect this. Protein has a higher TEF than carbohydrates and fat. Roughly 25% of the kcals from protein eaten will be lost as heat, whereas only around 70–75% will be absorbed. Carbohydrates may lose 10% as heat, whereas fat may only lose 2-3%.
Another reason why diets high in protein can help with fat loss.
Am I fat because of a slow metabolism?
The likelihood is no, rather down to an imbalance in how much you’re eating compared to how much you’re expending through activity. This is one of the reasons why I recommend tracking what you eat, so you can see how much you’re currently eating compared to how much you should be eating.
If you want out free tracking check list click here to download it
The use of a whoop band or activity tracker is also a method to help estimate your kcal expenditure day to day.
In some (pretty rare) cases, hypothyroidism (underactive thyroid), Cushing's syndrome, starvation, excessively low energy diets and low testosterone may slow your metabolism.
If you were concerned about your metabolism, then an RMR test will be able to determine how many kcals you require and whether or not it is something you need to worry about.
How can you speed up your metabolic rate?
1. Increase NEAT - Move more
As previously mentioned, increasing your NEAT can have a significant impact on how many kcals you burn in a given day. So make the effort to get your 10,000 steps in, take the stairs rather than the lift, walk further for lunch or to work, and generally make a conscious effort to be more active.
A combination of resistance and cardiovascular exercise can increase your metabolic rate. Typical endurance exercise will burn a lot of kcals during activity, whereas high intensity training will also increase the number of kcals you burn after you have finished. Resistance or weight training will increase the number of kcals burned at rest, during exercise, and to help build and repair muscle. This is the reason why we recommend a combination of all three (goal dependent!).
3. Fuel your performance
Chronically low kcal diets can have serious implications on your health, performance and metabolism. Low energy availability or relative energy deficiency in sport (RED-S), is a ‘mis match’, or, being left with insufficient kcals for the body to be healthy and function correctly. This is the reason why you should base how much you’re eating from an estimation of your total energy expenditure.
4. Eat a protein rich diet
Diets rich in protein are known to improve body composition (reducing fat mass and increasing muscle mass). As previously mentioned, protein has a high thermic effect of feeding making it an “inefficient" fuel source. It is also less likely to be stored as body fat and provides the foundations to build new muscle.
To sum up
If you’re worried about being a slow burner:
Figure out your RMR using metabolic testing or using our macro workbook
Note down your activity (use a fitness wearable)
Track your food intake
Make adjustments to your food intake
To book your RMR test (how many kcals you burn at rest) head over to www.boxnutrition.co.uk/metabolic-testing
Or check out www.boxnutrition.co.uk/sign-up for more help with building your diet.