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Why Is Losing Weight So Hard? | Nutritionist Explains | Myprotein
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Jan 30, 2025
Why is losing weight so hard? We got a nutritionist expert to explain some of the reasons why you may be struggling to shift those pounds. At some point in life, the majority of people will probably try some sort of diet or exercise regime to kick-start their weight loss goals, right? The diet industry in the US alone was estimated to be worth a staggering $71 billion in 2020 – so it's safe to say a lot of people are in the same boat. But why is it so difficult to get the results that you're after? We got our myth-busting nutrition researcher, Richie Kirwan, to explain some of the issues surrounding dieting and weight loss. Find Richie on Instagram: @be_more_nutrition *** Chapters: 00:00 - Introduction 00:24 - The weight loss industry 00:45 - What is your metabolism and how does it affect weight loss? 02:10 - How BMR affects your weight 03:42 - Is an efficient metabolism a good thing? 06:30 - How your appetite changes when losing weight 07:23 - The evolution and history of weight loss 09:29 - How our food environment affects weight 11:02 - Got any more questions about weight loss?
View Video Transcript
0:00
anyone who's ever tried to lose weight
0:02
will know that it's damn hard but why
0:04
exactly is that
0:06
science has a few answers
0:11
how's it going guys my name is richie
0:13
kirwan and today we're going to talk
0:14
about the many reasons that losing
0:16
weight is so hard from biological
0:19
reasons to the even more important
0:20
reasons that most people don't even
0:22
think about just to start with a little
0:24
context for this video the us weight
0:27
loss industry was worth an estimated 71
0:31
billion dollars in 2020. so clearly a
0:34
lot of people are willing to spend a lot
0:35
of money to lose some weight if it was
0:37
an easy thing to achieve i don't think
0:40
it would be that lucrative of business
0:42
so what is it that makes losing weight
0:44
so hard let's start with metabolism
0:47
everybody knows or you're about to find
0:50
out at least that your metabolism is
0:52
made up of a number of different
0:54
components you have your basal metabolic
0:56
rate or bmr your non-exercise activity
0:59
thermogenesis or neat your exercise
1:02
activity thermogenesis and the thermic
1:04
effect of food or tef which is sometimes
1:07
also called diet induced thermogenesis
1:10
your bmr is the energy that your body
1:12
uses to maintain all the essential
1:15
metabolic processes when you're at rest
1:17
in other words it's the energy that you
1:19
need just to stay alive neat is all the
1:22
energy you use for activity that isn't
1:24
specifically exercise like walking from
1:27
your car to the office
1:28
scratching your head carrying your
1:30
groceries fidgeting in your chair
1:32
moving your arms like a crazy person all
1:34
that stuff tef is the energy that you
1:37
burn just processing the food that
1:39
you've eaten and that varies based on
1:41
the macronutrients that you consume and
1:43
eat is all the energy you spend when
1:46
exercising and all of these components
1:48
together make up your total daily energy
1:51
expenditure or tdee if you're interested
1:53
in learning more about all this a lot of
1:56
the information in this video came from
1:57
an excellent review paper from
1:59
trexlertal titled metabolic adaptation
2:01
to weight loss implications for the
2:03
athlete for the moment we'll just focus
2:05
on the first two components bmr and neat
2:10
because bmr is the energy we need to
2:12
keep our body alive if you have a bigger
2:14
body you'll burn more energy simple as
2:17
that that's the reason why all online
2:19
calorie calculators ask for your body
2:21
weight muscle body fat and all your
2:23
internal organs use energy
2:25
the more of them you have the more
2:26
energy you use on the other hand when
2:28
you lose weight you lose body fat and
2:31
you often lose muscle and even some
2:33
internal organs can get a little bit
2:34
smaller what all that means is that as
2:36
you lose weight your basal metabolic
2:38
rate drops too so as an example if
2:40
somebody starts a diet at 2000 calories
2:42
and they're happily losing weight for a
2:44
few weeks eventually their weight loss
2:46
will slow down and eventually stop
2:48
because they're now a few kilos lighter
2:50
they have less body mass and they have a
2:52
lower bmr that's a pretty simple
2:54
explanation however in experiments where
2:57
they monitor people's bmr as they lose
2:59
weight scientists often find that bmr
3:01
actually drops lower than what they
3:03
would actually calculate for the amount
3:04
of weight that they've lost in other
3:06
words not all of the drop in bmr with
3:09
weight loss can be explained by the loss
3:11
of body mass so what's going on this is
3:13
where something called metabolic
3:15
adaptation or adaptive thermogenesis
3:18
comes into play you see when your body
3:19
realizes you're losing weight and has a
3:21
number of ways of doing that including
3:23
knowing when your calorie intake is
3:25
lower than normal or if your body fat or
3:27
muscle mass decreases it starts to think
3:29
you're starving so if your body thinks
3:31
you might not have enough food it starts
3:33
to do everything it can to reduce energy
3:35
expenditure it does this in a number of
3:38
ways but in general it tries to make
3:40
your metabolism more efficient now
3:42
whenever someone hears efficient
3:44
metabolism they often assume that means
3:46
it must burn loads of calories right
3:49
actually it's quite the opposite and to
3:51
help you understand this try thinking of
3:52
a car engine cars back in the 60s and
3:54
70s were famous for being gas guzzlers
3:56
and having really poor mileage so you
3:59
could fill it up with fuel and it
4:00
wouldn't be long before you needed to
4:02
refuel again why because the engines
4:04
were very inefficient and a lot of the
4:06
fuel that should have been used for
4:08
moving the cars was lost as heat or
4:10
sound or exhaust fumes since then engine
4:12
design has become a lot more efficient
4:14
and now we can travel a lot further on
4:16
the same amount of fuel the same applies
4:18
to your body a more efficient metabolism
4:21
uses fuel our food and fat stores more
4:23
efficiently and burns less how exactly
4:26
does this happen well one pretty well
4:29
researched theory is an increased
4:31
mitochondrial efficiency remember
4:32
mitochondria from biology class they're
4:34
the tiny organelles that act as the
4:36
powerhouse of the cell literally every
4:39
biology book ever made says that they
4:41
help convert carbs and fats into energy
4:43
or specifically into atp adenosine
4:46
triphosphate the energy currency of the
4:48
cell they do this by transferring
4:50
protons across the mitochondrial
4:52
membrane a process that is coupled with
4:54
atp production however that process
4:57
isn't always efficient and sometimes
4:58
protons leak across the membrane and
5:01
don't produce atp this is called
5:03
uncoupled respiration and some
5:05
experiments show that it actually forms
5:07
a really big part of energy expenditure
5:09
under normal conditions so for example
5:10
in rats it can be up to 20 of basal
5:13
metabolic rate however when we diet and
5:16
get fewer calories in normal we see a
5:18
drop in proton leak or uncoupled
5:19
respiration there are possibly a few
5:21
reasons for this like a lower production
5:23
of uncoupling proteins and i drop in
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hormones like leptin and thyroid hormone
5:26
which happens when we don't get enough
5:28
calories but wait there's more not only
5:31
does your metabolism slow down to
5:33
prevent further weight loss your body
5:35
even stops moving to stop you burning
5:38
too much energy remember i mentioned
5:39
non-exercise activity thermogenesis all
5:42
that movement that you do that isn't
5:43
exercise well when you're dieting your
5:46
body tries to reduce that too that means
5:48
you move less in your chair or walk less
5:51
or even smile less think of it like this
5:53
if i was deep in a calorie deficit right
5:55
now i wouldn't be moving as much as i
5:57
usually do i'd be pretty damn lifeless
6:00
kind of like this
6:02
here's another interesting piece of info
6:04
when people who don't gain weight easily
6:06
eat a lot of extra calories they often
6:08
subconsciously increase their need which
6:11
helps them burn off those calories and
6:13
maintain their weight so it clearly
6:14
works both ways protecting against
6:17
excess weight loss
6:18
and weight gain to make things even more
6:20
difficult not only does your body down
6:23
regulate metabolism and movement when we
6:25
start losing weight it also does a
6:27
number on your appetite i mentioned
6:29
leptin earlier leptin is a hormone
6:31
produced by our fat cells and generally
6:33
the more fat you have on your body the
6:34
higher your leptin levels are leptin is
6:36
a satiety hormone meaning it helps to
6:39
reduce appetite so when we lose body fat
6:41
or even when we eat fewer calories than
6:43
normal we produce less leptin and hunger
6:46
increases there's also ghrelin which is
6:48
another hormone produced in the stomach
6:50
that has the opposite effect of leptin
6:52
it increases hunger and when we fast
6:55
restrict calories or potentially when we
6:57
lose muscle mass from dieting ghrelin
6:59
increases and makes you want to rob a
7:01
bakery and that's just the tip of the
7:04
iceberg when it comes to all the changes
7:05
that happen in our body that make it
7:07
harder for us to lose weight from a
7:09
slower or more efficient metabolism to
7:11
reduce movement and increased hunger our
7:13
bodies really do try as hard as they can
7:16
to prevent weight loss but why try so
7:18
hard
7:19
for that we have to think in terms of
7:21
our evolution
7:23
when animals evolved our food supply
7:25
wasn't always plentiful and our
7:27
ancestors both human and much further
7:29
back would probably have had to deal
7:30
with food shortages all the time as food
7:33
was never guaranteed our bodies had a
7:35
lot of pressure to evolve ways to deal
7:37
with that think about it if you were
7:39
living on the plains of africa 200 000
7:41
years ago and there was a famine who do
7:43
you think would live longer someone
7:45
who's super active with a super fast
7:47
metabolism that's burning fat all the
7:48
time or someone who slows things down
7:51
and spares the little body fat that they
7:52
have making it last longer that's why we
7:54
reduce our metabolism and reduce
7:56
non-essential movement when our bodies
7:58
figure out food is in short supply we're
8:00
trying to save as much fuel or body fat
8:03
as possible to make us live longer on
8:05
top of that making us hungry when we
8:07
lose weight is a good way to make sure
8:09
that we seek out food and eat as much of
8:11
it as possible when it's available we
8:13
need to be able to build up our fat
8:15
stores to help us survive the next
8:16
famine
8:17
it's very hard to fight with millions of
8:19
years of evolution built into our genes
8:22
telling us to eat more by the way some
8:24
of you may be thinking is this the
8:26
famous starvation mode
8:27
when you drop calories too much and
8:29
can't lose weight
8:30
well yes but no the idea of starvation
8:33
mode is probably based on this science
8:36
because most stupid ideas about
8:37
nutrition in the popular media do have a
8:40
grain of truth to start with but it's a
8:42
big but
8:44
if you're dieting and losing weight and
8:46
your weight loss eventually stalls
8:47
because of all these mechanisms i've
8:49
just mentioned you can restart weight
8:51
loss by just dropping calories again or
8:53
increasing exercise it's not a hard
8:55
ceiling on weight loss like some people
8:57
try to make you believe that said you'll
8:59
get to a point where dropping calories
9:01
isn't really realistic or healthy
9:03
anymore in which case weight loss may be
9:05
painfully slow this is exactly what
9:07
happens with physique athletes who diet
9:09
down for a show eventually weight loss
9:11
is so slow that they're talking of
9:13
losing minuscule quantities of fat over
9:16
the last few weeks before show
9:18
and that's not for everybody but you
9:19
know what there's probably another
9:21
reason that may be even more important
9:23
for explaining why losing weight is so
9:25
hard and it has absolutely nothing to do
9:28
with you think about it the biology of
9:30
human beings has been pretty stable for
9:32
thousands of years but having a lot of
9:34
excess body fat only started to become a
9:36
lot more common in the last 50 years or
9:38
so so what changed our food environment
9:43
we now live in a world where we can eat
9:46
whatever we want whenever we want it at
9:48
least for many people in the developed
9:50
world for many scarcity and hunger is
9:53
not something they ever need to think
9:54
about you can order your starter main
9:57
course and dessert from three different
9:58
restaurants and have it delivered to
10:00
your door without ever having to leave
10:02
your sofa processed foods are everywhere
10:05
they're cheap they're designed to be
10:06
delicious and because most of the
10:08
calories come from refined carbohydrates
10:10
and added fats they don't fill you up so
10:12
you can just keep eating and eating on
10:14
top of that food advertising is
10:17
everywhere we look and even if you don't
10:19
think so it is affecting your buying
10:21
decisions and makes you want more food
10:24
maybe not right away but at some point
10:26
and because of that the amount of
10:27
calories that people eat has been
10:29
increasing for decades we live in what's
10:31
known as an obesogenic environment an
10:34
environment where gaining weight is easy
10:36
because getting food is easy and we're
10:38
encouraged to eat more through
10:39
advertising consequently losing weight
10:41
is very very hard i know this whole
10:43
video might seem a bit negative but the
10:45
whole point is if you struggled with
10:47
weight loss in the past i want you to
10:49
know that it's not your fault our
10:51
current food environment that focuses on
10:53
excess and our long-term survival focus
10:56
biology combine to make losing weight
10:59
damn hard yes losing body fat is
11:01
possible and knowing this information
11:04
focusing on sustainable nutrition and
11:05
learning how to manage your food
11:07
environment play a big role in making
11:09
that happen that'll be a whole other
11:10
video sometime so what do you think did
11:13
that clear things up for you about why
11:15
losing weight is so hard as always if
11:17
you have any questions let me know in
11:19
the comments below and remember to like
11:21
and subscribe to the my protein youtube
11:22
channel for more great evidence-based
11:24
nutrition information
11:29
[Music]
11:34
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