Exercise in any form, be it walking, running, dancing, cycling or resistance training has a major part to play in our health and well-being. Exercising for even 30 minutes a day can provide significant benefits to your physical and mental health.
Exercise and the gym plays it's part in weight management and obesity and is seen as the key to helping people stay in shape and lose weight, but just how effective is the gym for weight loss?
I imagine the majority of people who go to the gym do so to be healthier, feel good, and look good too.
Many people will invest in a gym membership with the belief that it is the key to their success.
So why do so many people who go week in week out look exactly the same years later?
Because people focus too much on exercise and not enough on their nutrition and lifestyle!!!
Quite frankly, people think the gym will do more for them than it actually does.
They assume because they go to the gym that it will equal out their lifestyle but we have all heard the cliche saying "you can't out train a bad diet".
When I was a PT I would see people take part in a low to moderate intensity group class or exercise session and then sit in the cafe with a milky coffee and a cake...and then wonder why they aren't losing weight.
As hard as exercise can be at the time, it has often been said to me that going to the gym and "feeling the burn" is much more worth it than having to change their diet or manage their lifestyle.
But focusing on exercise and the gym for weight loss may be a waste of your time.
Exercise and energy expenditure
The purpose of exercise if your goal is weight loss is to help create a Calorie deficit, by increasing the amount of energy we use.
The issue is exercise only makes up approximately 5% of your daily energy usage.
This means when people put all their effort and attention in to exercising, they are focusing on a small piece of the puzzle.
How exercise impacts energy expenditure is also mixed with huge individual variability.
Some studies show that when people exercise it increases their overall energy expenditure (energy burnt), which you would expect right?
But other studies show exercising actually decreases overall energy expenditure as people then compensate by reducing their typical daily activity levels (Hall et al., 2012).
This means that for some going to the gym may even result in less energy expended over the course of the day and week.
How does exercise impact appetite?
Not only can exercise have a wide variability on people’s overall energy expenditure but it can also affect appetite and energy intake.
Exercise may reduce hunger and appetite post-exercise by altering appetite regulating hormones.
You may have experienced it yourself, after a good training session when you really don’t want to eat.
Exercise tends to reduce acylated ghrelin (a hormone that increases appetite) and increases PYY and GLP-1, two hormones which make us feel more full (Schubert et al., 2013).
However, for others, exercise can potentially lead to increased appetite and eating more. Blundell and King (1999) found exercise didn't affect appetite in 65% of participants and whilst 16% of participants had a decrease in energy intake, 19% increased energy intake.
Interestingly, studies show appetite is more likely to decrease in overweight or obese individuals whilst those classed as leaner participants are more likely to see an increase in appetite.
The type of exercise may also play a role in its impact on our appetite and energy intake.
Aerobic exercise has been shown to reduce neuronal responses in the brain which reduces food pleasure and reduced motivation to eat (Evero et al., 2012).
This suggests aerobic exercise may help reduce the motivation to eat, especially pleasurable foods which tend to be higher in Calories.
Individuals who do moderate to low levels of exercise are more likely to experience exercise-suppressed energy intake whilst those who have high levels of activity are more likely to see the opposite (Schubert et al., 2013). However, this doesn’t mean those that exercise more and use more energy then manage to eat all those Calories back.
How exercise impacts men and women
Using physical activity to lose body fat is more effective in men than women according to Hagobian and Braun (2010). In fact, exercise without an accompanying reduction in Calories is not very effective for weight loss in women at all (Jakicic et al., 2006).
Studies that recorded 16 months of supervised aerobic exercise found men who ate ad libitum (what they want, when they want) lost body fat whilst there was no change in women who did the same.
This suggests that after aerobic exercise, women are more likely to re-compensate the energy they use by eating more, therefore not losing body fat.
Sex-based hormones may alter appetite, energy intake and energy expenditure that stimulate appetite and energy intake whilst potentially suppressing energy expenditure in women.
Hagobian and Braun (2010) found women had increased ghrelin and reduced insulin which would likely increase appetite whilst a further study found similar results with decreased leptin and insulin levels after 12 weeks of exercise in women.
Nutrition vs Exercise vs Nutrition AND Exercise
Now so far, I have highlighted that increasing exercise can help create a Calorie deficit, however, the affect it has on our appetite and intake can differ from person to person.
But what is the most effective way of losing weight? - is it to focus solely on the nutrition, on exercise or combine both?
Johns et al., (2014) conducted a meta-analysis and systematic review of 8 studies that looked at the age old question of what is the most effective way to lose weight. The studies which were made up participants (predominately female) with a BMI of >25kg/m2 and were placed in 3 separate groups 'nutrition only', 'exercise only' and 'combined weight programme'. They found that at the 3-6 month stage, there was no significant difference between the nutrition group and the combined group, however, compared to the exercise only group, the combined group lost an average of 5.33kg more.
Not surprisingly, at 12-18 months follow up, the difference between 'exercise only' and the 'combined group' grew further at 6.3kg (~1 stone).
What was interesting was that at 12 to 18 months, the combined group outperformed the nutrition only group with an average increased weight loss of 1.72kg.
What this review of studies suggests is in the short term, focusing on nutrition only is as effective as a combination of nutrition and exercise, however in the long term, the combination is more beneficial. It also suggest exercise alone is not as effective for weight loss.
What does this all mean?
Overall, studies suggest people react differently to exercise with some eating less, some eating more but the majority with no change.
Studies state that it is unlikely that exercise increases people’s appetite to the point that they gain weight, but that exercise can reduce overall movement and energy expenditure, reducing the deficit and impact of the exercise in the first place.
A look at the age old question of exercise vs nutrition vs combination indicates that the medals go to:
Gold = Nutrition AND exercise
Silver = Nutrition only
Bronze = Exercise only
In simple terms this means unless you consciously take action to reduce your energy intake through nutrition, going to the gym or exercising alone will not do much for your weight loss goals.
To conclude, you can not rely solely on exercise to help you achieve your weight loss goals.
You must adapt the way you eat!
You should try to move more!
You must make positive changes to your lifestyle!
If you're struggling with your weight and would like expert help from someone who has over 15 years experience, get in touch.
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