For many people, with pretty much every season, a new season of ‘trying to lose weight” begins. Everything from trusted old plans to brand new fads are dusted off and tried on by people eager to shed a few pounds. And every few years a new diet hits the news and blows up into a big sensation. But in reality, there are very few combinations of patterns that compose diets. All diets work by ensuring we create a calorie deficit, usually by getting us to eat less. They can do this by:
- Encouraging us to suppress our appetite.
- Encouraging us to count and use our willpower.
- Encouraging us to eat foods that fill us longer.
Here, we are exploring how low carbohydrate, high fat diets work to suppress our appetites and fill us up, making it easy to lose weight with minimal exercise and without counting points, calories, or portions.
What is low carb?
Low carb means “low in carbohydrates”. Naturally, a low carbohydrate diet involves going below the recommended amounts, or at least the low end of it. The USDA recommends 130g of carbohydrates a day. At 4 calories per gram, that is 520 calories. Obviously, this depends on your personal calorific intake. The USDA also advises that 45-65% of calories should come from carbohydrates in an average diet. In a 2000 calorie a day diet, this would mean 225-325 grams of carbohydrate, or 900-1300 calories from carbohydrates. Therefore, a low carb diet begins at 225 grams of carbohydrate, all the way down to 130 grams of carbohydrate. Any less and it is a very low carbohydrate diet.
Low carb, in and of itself, means nothing else specifically. You could eat all 130-225 grams from sugars, or from apples, or from potatoes. You could still eat the usual amount of proteins or fats. The details of this diet are what make all the difference. So now we’ve seen what low carb means, what does high fat mean?
What is high fat?
High fat, much like low carb, is a relative term. The USDA recommends that 20-35% of your calories come from fat. That means 400-700 calories for a standard 2000 calorie diet. But as fat is so high in calories, with 9 per gram, it works out as a very small amount. 44-78 grams of fat. This means that “high fat” begins at the upper end of what is recommended: at 30-35%, or 67-78 grams for a 2000 calorie diet. This already classes as “high fat”.
However, many high fat dieters will happily eat 100 grams of fat a day or more. There technically is no upper limit to a “high fat” diet. Some adherents have been known not just to eat bone marrow and bacon (which are delicious ways of keeping your fat intake up) but to munch on pure butter, drink cream, and eat coconut oil off a spoon. Naturally this is unappealing to many of us, but don’t let it scare you away from low carb, high fat diets. To eat low carb, high fat, you could be eating 130 grams of carbs and 70 grams of fat a day. That’s almost twice as many carbs! And carb-rich foods tend to also be loaded with fiber and water. You will most likely find your plate is, by volume, 60% greens, 20% starches, and 20% meat. And that would be a low carb-high fat dinner!
Isn’t fat bad for you?
For starters, even at the peak of the low-fat craze we knew that fat was vitally important to our bodily functions. Firstly, it lets us process protein, preventing a problem called “rabbit starvation”, where our brains, muscles, and organs waste away, no matter how many calories we are eating, because we’re eating too much protein and not enough fat! Fat is also what our brains, bone-marrow, and much of our organs is made of. And to boot, our body fat is the largest endocrine (hormonal) organ in our bodies. So, we’ve never thought fat was bad, we just thought for a brief period in time that it was bad to eat over 50 grams of it a day.
And now we’re discovering that certain types of fat are bad for us… and it’s not the ones we think! Cholesterol used to get a bad rap, but has been found to do nothing at all to our blood cholesterol balance. Then we assumed it was saturated fats, but coconut and other nuts are loaded with saturated fats, as are oily fish, but they’re good for our hearts and brains. It turns out there are actually two classes of fat that are bad for us:
- Heavily processed fats. Trans fats, homogenized fats, pasteurized fats, etc, are all heavily oxidized and bad for us. This includes when we eat deep fried foods, as oil quickly burns and goes dark, becoming a bad fat! Only lard is heat-stable enough for deep frying, and no restaurants use lard since the scared about cholesterol and saturated fats.
- Fats from animals that had been fed unnatural diets. When cows eat corn, chickens eat bread, and salmon eat pellets, their fat content changes. They grow more bad fats, and fewer omega-rich good fats. This results in an animal that is bad for eating all round.
When choosing your fats, you can’t just pick a type of fat and trust it will be good, always choose:
- Naturally grown
- Healthy plants/animals
- Minimally processed
- Never pasteurized
Are all low carb diets high in fat?
Not at all. Firstly, some low carb diets are low in fats too, promoting protein consumptions. On this diet, you will never eat very low fat or carbs, you will probably eat 100 grams of carbs and 20 grams of fat a day, to prevent rabbit-starvation. But you will not eat more fat, instead, you will actually restrict it. This diet is rarely sustainable in the long term because of the amount of protein many people eat on it. Even when you avoid rabbit-starvation, relying on protein for too long can upset your kidneys, change your gut flora, or just make you hungry all the time. Protein is a very satisfying nutrient, but it usually comes with very few micronutrients. After a while eating a diet very rich in protein, our bodies often crave vitamins and minerals, resulting in hunger pangs. This can even happen if you take multivitamins!
Secondly, there are some low carb diets where your fat intake doesn’t change at all. Of course, as a percentage this will make it look high fat. But gram for gram, you may only be eating 50 grams of fats, which is well within normal boundaries. This is more a numbers trick than anything else. The way these diets work is that by cutting down carbs without eating any extra protein or fat to compensate, your calories are reduced. Many people following this diet will just stop eating primary carb sources. This means no grains, no potatoes, no fruit, and definitely no cakes and candy. But they don’t put anything else on their plate instead! So, they serve themselves their salad and chicken, but without chips, or have eggs and sausage, but with no muffin. This means they can eat less without much effort, and they will lose weight.
How does reducing carbs help you lose weight?
Changing your nutrients around will not help you lose weight unless you create a calorific deficit. In this case, we create a deficit by removing cravings and hunger pangs. Most people don’t have an “off switch” for carbs, and especially not for carbs and fats together! This means that the more carbs we eat, the more we want to eat. This is why when we eat ice cream, pasta, or cake, we can just keep eating and eating, often until we feel physically stretched. Our bodies recognize these foods as vital and rare – which they were back when we were apes – and then our bodies demand more of these rare foods. By reducing the amount of carbs we eat, we can fight these cravings. And the less we crave, the easier it is to stick to our diets. Research on thin people who have never been fat has revealed they can get fat, and that the main reason they don’t is that their cravings for food are so much gentler than those of fat people. This means that if we can find ways of reducing the intensity of our cravings, we can lose weight too!
How does eating more fat help you lose weight?
So that makes sense, but where does eating more fat come in? Some people find that fats on their own have the opposite effect to carbs. Remember how earlier we discussed how some people on high fat diets will eat pure fats? And remember that some people, probably most people, find that idea completely, stomach-churningly repulsive? This is because we do have an “off switch” for fats. Unlike carbs, which we either absorb all of (sugars) or pass out when we don’t need them (starches), too much fat gets into our systems and overwhelms the organs designed to handle it. If we eat too much fat, our pancreas, small intestine, and gall bladder can become ill. This results in abdominal pains, black tarry stools, or even organ failure. For this reason, our bodies tell us when we’ve had enough fat and then we can stop. This means that eating higher fat contents in our meals will encourage us to stop eating sooner, which reduces our calorie intake.
Furthermore, fats also slow our digestion right down. Because they are digested in multiple stages, they move very slowly through our bodies. Which means anything we ate with those fats moves through us slower too. This has two key effects on the body. Firstly, it lowers the glycemic index of our foods. Because the carbs are wrapped in a fatty layer that needs to be digested before we can start working on the carbs, fats lower the glycemic index of our meals. This means that our blood sugars rise slowly and steadily, and never hit a dangerous peak. Which in turn means our insulin doesn’t have to work as hard to control our blood sugars. It’s insulin’s job to move free sugars in the blood into muscle and fat tissue. If the sugars rise slowly, they are more likely to go to muscle to be burnt. If they rise fast, they are more likely to be moved to storage in our fat, to prevent us from suffering high blood sugar. For this reason, eating fats may help us avoid storing fat.
Secondly, as the fats we eat slow down our whole digestive tract, this gives our bodies more of a chance to properly digest all of our food. Often a lot of what we eat isn’t fully digested by the time it reaches our colon, so we miss out on many vital nutrients. If we slow down our digestion, many things are processed better. We digest and absorb more proteins, resulting in needing to eat fewer. We break down more fibers, resulting in healthier, better fed gut bacteria. We absorb more water, resulting in less thirst and less need for minerals. And we absorb more vitamins and minerals themselves, resulting in less need for more food. All in all, slower digestion means we get more out of our food. If we normally get 40% of the nutrients from a food that is 100 calories, we may eat 200 calories of it, to get more nutrients. But if we get 80% of the nutrients with our first go, then we don’t need to eat more of it, and we have only eaten 100 calories! That is another way that eating high fat helps control your appetite.
Can I do IIFYM?
IIFYM means “if it fits your macros”. This means that you establish yourself an allowance as to how many grams of carbs, fats, and proteins you can have, but that quality of the food doesn’t matter. Many bodybuilders, for example, follow this rule. They will eat burgers, pizza, doughnuts, and still lose weight.
On the one hand, you definitely can do IIFYM on low carb, high fat diets. As long as you are eating low carb and high fat, the diet will work and you will feel less hunger, eat less, and lose weight. There is no reason for it to stop working entirely just because you are doing it with junk food.
But on the other hand, doing a low carb, high fat diet with junk food makes it unsustainable and less effective. You can’t eat junk forever, as it takes its toll on your body. So eventually you will have to change your diet. And because part of the effectiveness of low carb, high fat, comes from better absorption of nutrients, if you don’t eat enough nutrients you will feel hungrier than someone eating healthy foods.
What’s the difference between low carb, very low carb, and keto?
If low carb covers basic restriction to 120-225 grams a day, then anything under 120 is considered very low carb. A very low carb diet may be required if you are very heavy, if you have plateaued and can’t manage to lose weight, or if your cravings for carbs are very strong. These diets are very difficult to sustain, and are usually best used briefly, to speed up your weight loss. Many people on these diets will eat only incidental carbohydrate, coming from leafy greens or tomatoes. They will avoid starches and fruits, as well as all added sugars.
The minimum recommended is 45 grams of carbohydrates a day. That is 180 calories. Anything under this can cause what is known as ketosis. Ketosis is where you aren’t eating enough carbohydrates to fill your blood with glucose, so your body has to make do and create its own fuel. The process is actually more for when there is a famine and we need to survive off our own muscle and fat until more food is found. Our body combines fats and proteins into ketones, a sort of fuel similar to glucose. Following a ketogenic diet can cause very rapid weight loss, especially if it’s low fat, as your body will burn its own fat to make ketones. Many people on this diet will avoid most plant matter other than leafy greens, to keep their carbs as low as possible. This diet is almost entirely unsustainable.
Is a low carb, high fat diet for everyone?
Pregnant and breastfeeding women should beware restricting carbs too much, as glucose is essential to ensure the growing fetus and baby get the best nutrition possible.
Menopausal women may experience a worsening in their symptoms, as low carb diets often reduce our estrogen levels and boost our testosterone. If you do, stop the diet until the worst of the menopause is over.
People who do regular cardio activity will benefit more from their diet if they keep the carbs up. 200-300 grams a day may be more than enough, but if you eat less than that you could harm your stamina and recovery.
Diabetics and pre-diabetics will need to consult with their doctor before dramatically changing their carb intake.
People suffering from gall bladder issues, or pancreatic failure, should not eat a high fat diet. High fat diets are difficult to digest, and if your pancreas or gall bladder are damaged, missing, or failing, then you will get very ill on this diet.
What are some popular low carb, high fat diets?
There are many diets that follow a low carb, high fat pattern. The Atkins diet is the most famous of all, but some variants of the Paleo diet (including the Primal diet) are also higher in fats. The Scandinavian diet is also very popular right now, and many other diets, such as points-based ones or fasting diets, can be adapted to a low carb, high fat form to help curb your appetite. As long as you’re eating healthy, whole foods and responding to your body, there is no right or wrong way to do this diet.
Is this a good maintenance diet?
If you lost weight on this diet slowly, and you are eating a healthy variety of whole foods, you can absolutely use this diet for maintenance. Simply increase your calories whilst keeping the percentage of fat, carbs, and proteins the same. You could eat a low carb, high fat diet indefinitely if your body is up for it.