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is a low-carb diet better than a low-fat
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diet for fat loss let's talk about that
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how's it going guys my name is richie
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kirwan and today we're going to talk
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about one of the greatest nutrition
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rivalries of all time you see people
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always want to know which is the best
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approach be it conventional versus sumo
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deadlifts it's conventional by the way
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cardio versus weights weights one's
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hands down vegan versus carnivore
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personally i'm a big fan of the kearney
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vegan diet and today we're going to talk
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about the difference between low-fat and
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low-carb diet approaches and which if
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any is better for fat loss along the way
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we'll also talk about how our body
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stores and burns fat and how weight loss
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and weight gain happen before i go any
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further i want to point out that i'm not
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going to recommend any specific diet in
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this video in my opinion one of the most
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important factors of any diet is
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someone's ability to enjoy it and stick
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to it long term that means that the diet
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one person can stick to really easily
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may be very different from a diet that
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someone else enjoys and can adhere to if
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you take anything from my videos i
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really hope you learn that you don't
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have to restrict yourself to believing
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in one single dietary approach for
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everyone humans don't work that way and
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neither do diets so first off i think
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it's a good idea to talk about how we
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actually burn fat in the first place our
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body fat is called adipose tissue and
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one of its main functions is to store
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energy in the form of triglycerides a
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triglyceride is a molecule made up of
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three fatty acids joined to a molecule
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of glycerol triglycerides or fats are a
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really great way of storing energy
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because they can store a lot of energy
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compared to other macronutrients one
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gram of triglycerides or fat stores nine
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calories whereas one gram of either
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protein or carbohydrates stores only
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about four calories meaning they're less
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than half as efficient for energy
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storage that said our body does store
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some carbohydrate in the form of
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glycogen in our muscles and liver and
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uses this to maintain our blood glucose
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levels when we haven't eaten and as a
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fuel for high intensity exercise when we
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haven't eaten in a while when blood
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glucose levels are normal and when we're
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not exercising intensely our body gets
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energy from our body fat an enzyme
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called hormone-sensitive lipase breaks
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down triglycerides to glycerol and fatty
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acids those fatty acids get exported out
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of the fat cell and are transported in
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the blood attached to a protein
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transporter called albumin these free
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fatty acids travel around the body to
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provide fuel for cells simple right now
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if we burn more fat from our fat cells
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than we eat over time we lose body
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weight now when we eat a meal with a mix
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of protein carbs and fats something
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different happens when we digest our
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food protein and carbs get absorbed
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directly into our bloodstream from the
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gut in the form of amino acids and
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sugars the increase in blood sugar and
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amino acids causes our body to produce
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insulin which is a really important job
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it helps to bring our blood sugar back
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down to normal levels because high blood
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sugar for a long time can be bad for our
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health so there are a few ways that
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insulin brings our blood sugar back down
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the first thing is it inhibits hormone
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sensitive lipase so we don't get any
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more fat britain this means our body has
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to burn carbohydrates or amino acids
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instead for energy this means your body
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is in a glycolytic state burning glucose
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for energy insulin also increases
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storage of both glucose and free fatty
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acids to help get them out of your
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bloodstream glucose can be stored as
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glycogen and if your glycogen stores are
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at their limit then glucose can be
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converted to fat in the liver and stored
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as body fat free fatty acids get
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converted back to triglycerides and
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stored as body fat too so with this
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explanation it's very easy to think holy
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crap if i eat carbs and raise my insulin
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then i'm going to be storing fat all the
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time all i need to do is not eat carbs
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my insulin will be low i'll start
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burning fatty acids and i won't store
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any more body fat right while that makes
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a lot of sense on the surface it's
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actually way too simple a way of
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thinking about and completely ignores a
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very important point known as energy
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balance you see no matter what fuel we
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use carbs or fats our body still needs
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to use the same amount of energy to be
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alive and active more or less if you
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don't eat enough food to meet those
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needs your body will be in a negative
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energy balance and over time you'll lose
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body fat on the other hand if you eat
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more food than your body needs to burn
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to survive this is called positive
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energy balance that extra energy you get
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from your food needs to go somewhere our
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bodies in general don't like waste so
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that extra energy will get stored as
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either glycogen if there's room or body
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fat which humans have a virtually
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unlimited storage capacity for and over
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time that leads to weight gain so if you
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go on a carb-free diet that doesn't
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spike your insulin and get most of your
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energy from fat while it might be nice
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to think that you won't be able to gain
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body fat because you're just burning fat
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the truth is different if you eat more
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fat you will burn more fat but you're
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burning the fat you're eating and if
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you're eating more fat than you burn you
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will store that extra as body fat
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because you don't need high insulin to
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store fat excess calories is more than
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enough okay so far anything i've spoken
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about is what we call the mechanism of
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fat loss but how does that all play out
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in practice do we have any weight loss
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studies that compare low fat with low
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carb well luckily enough we have a lot
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of such studies so let's talk about one
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of the best controlled low fat versus
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low carb studies which was run by kevin
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hall at the national institute of health
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in the us it had 19 participants with
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obesity the average body mass index was
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35 and it was performed in a metabolic
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ward that means that the participants
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lived in the research center during the
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experiment and all the food that they
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ate and exercise they did was monitored
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to the highest possible level it was a
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crossover design which meant that all
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the participants got to do both the
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reduced fat high carb and the reduced
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carb high fat diet for two weeks each
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with a two to four week washout period
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in between both diets were isocaloric
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which means they had the same calories
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and put the participants in a 30 energy
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deficit both diets also had the same
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amount of protein at about 20
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in nutrition science like this it's
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really important to be able to control
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as many factors as possible so that you
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know that any differences in results are
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caused by in this case the difference in
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carbs and fats so what happened well as
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you'd expect on the reduced carb diet
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insulin dropped more than 20 percent on
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top of that fat oxidation or fat burning
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increased a lot again as you'd expect
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considering the participants were
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getting most of their energy from fat
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now at this point i'm going to remind
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you that the extra fat oxidation is
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going to be a combination of burning
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body fat and burning the fat that they
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were eating but the interesting finding
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was the effect on just burning body fat
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which at the end of the day is what
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people care about when it comes to a
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weight loss study the researchers
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calculated that the reduced carb group
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was burning 53 grams of body fat per day
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but the reduced fat group was actually
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burning 89 grams of body fat per day so
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overall the reduced fat group was
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actually burning more body fat now this
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was just a two week study but it does
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help to show when it comes to burning
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body fat a calorie deficit seems to be a
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lot more important than keeping insulin
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low because remember that low carb group
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had lower insulin but we're burning less
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body fat what about longer term studies
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in the real world do we have any good
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studies comparing low carb and low fat
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diets you bet we do professor
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christopher gardner ran the diet fits
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trial which compared weight loss on a
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healthy low fat diet versus a healthy
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low carbohydrate diet for 12 months this
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was a free living experiment which means
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people were living their normal lives
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and we're told how to eat that means you
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can't monitor what the people do or eat
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as well as in a metabolic ward study but
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the results are a lot more realistic
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because people can't be controlled and
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told how to eat in the real life this
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study also had over 600 participants
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which made the results a lot more
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reliable all the participants were given
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education on how to either lower their
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carbs or fats as much as possible
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depending on the group that they were in
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the low-fat diet group had an average of
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48 carbs and 29 fat and the low-carb
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group had an average of 30 carbs and 45
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fat and i know people are going to say
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that's not very low carb low fat but
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this is what people do in the real world
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and what happened to 12 months well both
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groups on average lost weight the low
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fat group lost 5.3 kilos and the low
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carb group lost 6 kilos on average so
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they lost 700 grams more but this wasn't
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statistically significant and 700 grams
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over a year isn't really a meaningful
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amount of weight loss either also this
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study didn't look exclusively at body
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fat so part of the difference could be
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losses of body water which we know are
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greater on low carb diets on top of that
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the insulin levels of the participants
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had absolutely no effect on weight loss
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either what was really interesting about
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this study is that it was funded by the
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nutrition science initiative or nusei an
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organization that pretty much has the
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goal of proving that carbs and insulin
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cause weight gain so the fact that their
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study didn't show that was a pretty big
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deal i could talk about a lot more
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studies in detail but we have so many
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that we even have meta-analyses of
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studies a meta-analysis is when you
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combine the results of multiple similar
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studies to find out what the overall
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effect is now there have actually been a
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lot of meta-analyses comparing low-fat
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and low-carb and other diets over the
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years and they have more or less had the
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same results one of the more recent
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studies used data from 53 other studies
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with over 68 000 participants and a
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duration of 12 months the analysis
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showed that on average the low carb
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diets resulted in about
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1.15 kilograms more weight loss than the
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low fat diet again 1.15 kilograms over
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12 months isn't a big difference when it
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comes to body weight and we always have
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to think how much of that difference is
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body water and is there much of a
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difference if any in body fat with all
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the evidence that we have we can say
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that when it comes to fat loss low carb
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diets are probably just as effective as
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low fat diets we definitely don't have
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any evidence to say that low carb diets
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have any magic weight loss effect and we
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can also say that lowering insulin
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doesn't affect weight loss either so
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which should you choose low carb or low
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fat well that is completely up to you
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and what you prefer you see the most
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important factor when it comes to
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long-term body fat loss is being able to
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stick to a diet if you can't stick to a
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diet whatever diet it may be because you
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hate the foods you're eating then you're
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not going to be able to maintain that
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weight loss if you want long-term
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success you need to find a way of eating
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that you can enjoy and stick to long
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term for some people that might be lower
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fat for some it might be lower carb find
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what works for you and don't fall for
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all the divisive and dogmatic diet
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that you see on the internet every day
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as long as you eat fewer calories both
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low fat and low carb diets will work i
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really hope that's cleared up some of
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the confusion about low carb and low fat
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diets as always if you have any more
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questions let me know in the comments
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below and let us know about your own
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experience with low carb or low fat
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diets and remember hit that like button
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and to subscribe to the my protein
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youtube channel for more great
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evidence-based nutrition information