Weight loss is all about creating an energy imbalance. You want to be taking in less energy than you are using. But, all food isn’t equal. Some choices are more powerful for weight loss than others.
One option is a low carb diet. These are incredibly popular and they do have scientific support. But, does a low carb diet work for everyone?
After all, this diet approach is a departure from the normal nutrition advice we are given – and involves eating more fat and more protein than you might expect to on a diet.
What is a Low Carb Diet Anyway?
A low carb diet is mostly what the name suggests. With it, you significantly decrease your carbohydrate intake, compared to what is considered normal. You’ll typically increase fat and possibly protein to make up the energy difference.
In most cases, low carb dieters don’t actively count calories. But, many will keep track of the levels of carbs, fat and protein that they eat daily.
Even without counting calories, you often consume less on a low carb diet. This happens because the food is more filling and you’ll tend to get satisfied faster.
The term low carb is a general one and there are many different low carb diets out there. For example, some people may be eating less than 100 grams of carbs a day, others less than 20 grams.
What you choose depends on the outcomes you're looking for and what works best for you.
The Science Behind Low Carb Diets
There has been considerable research into low fat and low carb diets. The outcomes show that low carb diets are a good option. Not only do they lead to significant weight loss, but they have even been associated with some other health benefits.
For example, one study compared low carb to low-fat diets across a 12-month period. They found that participants following the low carb diet lost significantly more weight in the first 3 months and the first 6 months than those on the low-fat diet. The differences in weight were non-significant at the 12-month mark (1).
This outcome indicates that low carb diets can result in more weight loss early on, but lead to similar weight loss in the long-term. That suggests that low carb diets are at least as effective as low-fat diets.
At the same time, many people may find that losing more weight early on helps them to stay motivated. That may make people more likely to stay on the diet.
A second study looked at similar outcomes across a year and found that the differences were not statistically significant, although the low carb group did appear to lose more weight (2).
Another study found a similar outcome, with the low carb group losing significantly more weight across the entire study (3). That study only ran for 6 months, so it isn’t possible to tell whether the observed effects would have been the same after a year or not.
A 24-week study also found that low carb participants lost more weight, although, in that case, the results weren’t statistically significant (4).
A 12-week study in adolescents looked at weight loss in low carb and low-fat treatments. In both cases, the participants were not told to restrict their calories. The low carb group lost significantly more weight than the low-fat group in that study (more than twice as much weight loss) (5).
All of these studies support the idea that low carb diets are at least as good as low-fat ones for weight loss, and there are many more studies with similar outcomes that I haven’t examined in detail (e.g. 6,7,8).
In many cases, the observed health benefits were only present for low carb diets (and not for low-fat ones), or they were stronger in the low carb diets.
Why Diets are Tough
It seems like everyone is looking for an effective way to lose weight, and there are so many different diets out there to help.
With all that interest in weight loss, you would think that people find diets, follow them and lose the weight. But, losing weight is hard.
Compliance to any diet is difficult, for a wide range of reasons. For example, people often have an emotional attachment to food and turn to it when there is a crisis in their life or when they are emotional.
After all, a tub of ice cream or a bag of cookies goes hand-in-hand with a breakup. This means that no matter how hard people try, they often end up reverting to their old eating patterns.
Another factor is food addiction and the strong cravings that people get for food that they shouldn’t be eating.
There is also lifestyle to consider. If you have friends who like going out for meals or regularly eat fast food, the social pressure can make losing weight that much harder.
And I’ve only listed a few factors that make following a diet hard.
Successful weight loss is really about changing your lifestyle in a way that works for you. For some people, that change might be a low carb approach, for others, it might be something different.
Following a Low Carb Diet
There is this underlying assumption that low carb diets are harder to follow than low-fat diets. And, in fairness, they are somewhat restrictive.
But, at the same time, low carb diets have a major advantage.
With a low carb diet, you’re consuming more fat, more protein (most of the time) and less sugar than a conventional diet or a low-fat diet.
This helps to get around one of the worst parts of dieting – hunger. Typically, diets that are relatively high in protein tend to reduce hunger. Fat also tends to be more satisfying than carbs, which helps.
This means that you will often naturally eat less without even intending to.
That’s a major advantage if you’re trying to lose weight. That pattern can actually make a low carb diet easier to follow than other approaches.
Does a Low Carb Diet Work for Everyone?
With all the evidence supporting them, it seems like a low carb diet should work for everyone, especially for people that struggle with weight loss. But, that’s not entirely true.
Some people end up giving up and falling into old eating habits. For example, one study found that 75% of participants completed a 13-week low carb diet intervention (14). For a longer period, dropout rates would be higher.
Of course, this outcome isn’t unique to low carb diets. People often struggle with weight loss and may fail every diet they try.
Low carb diets can also be sustainable. After all, most people don’t count calories when following low carb, which makes them easier to follow. There are also some pretty amazing recipes out there, along with many detailed cookbooks to rely on.
This gives you the chance to still enjoy your food. You might even find that you prefer low carb recipes to conventional ones.
Once your body has adapted to low carb, you may also find that you have more energy, fewer cravings and are less hungry.
So then, it all sounds amazing, right? For many, a low carb diet is perfect. But, that’s not always the case.
There is No Single Best Solution
Low carb advocates often claim that this is the only way to lose weight and be healthy. Many also promote very low carb diets, such as a keto diet.
Yes, low carb diets can be healthy. For many people, they’re the perfect fit. But, as Precision Nutrition explains, such ideas ignore the complexity of our bodies and the differences between us.
At the end of the day, carbs don’t make you gain weight, nor does fat – not directly. Too much fat or too many carbs can contribute to weight gain, sure, but that’s not quite the same thing.
For that matter, many people make dramatic changes when they start low carb. This could include cooking more meals themselves, moving away from processed food and eating at home. Most will also be decreasing their calorie intake – whether they mean to or not.
Those practices account for many of the benefits of a low carb diet.
Is a low carb better than a low-fat diet? Honestly, the jury is still out.
It’s clear that fat isn’t as bad as we were once told while relying on processed food and added sugar is never a good idea. But, you can certainly lose weight on a low-fat diet and many people do. The same is true for low carb.
In many ways, the type of food you choose is much more relevant. Focusing on cooking your own food and on ingredients like vegetables, eggs, meat and fish is powerful for health and for weight loss.
Likewise, it’s important to find a solution that works for you. A diet or lifestyle will never be sustainable if it goes against your nature and your body’s needs. In contrast, one that matches you well will be easier to follow and much more powerful.
Low Carb Can be a Poor Fit
For some people, low carb simply doesn’t work for them physically. For example, some may find that their energy levels never increase or that they are moody all of the time.
Now, there is an initial adjustment period, often called the low carb or keto flu. This can be difficult, but those symptoms typically dissipate over time. Even taking that into account – not everyone will feel great on low carb.
Some people even gain weight on low carb, rather than losing it. The site KetoDietApp highlights 10 reasons why this may be, along with solutions. But, some people still struggle, even if they seem to be doing everything right.
A low carb diet can also be antisocial. You’re cutting out many of the foods that people consume at events and it becomes more difficult to eat out with friends and family.
This isn’t a problem for everyone and your health is more important than peer pressure. Even so, for people who enjoy and value social events, another type of diet may be a better fit.
A final problem is behavioral. A low carb diet is restrictive and can mean decreasing or cutting out many types of food. That includes pasta and bread, which many people love.
How dramatic this is depends on the type of low carb diet you follow and the choices you make.
Even so, some people don’t fare well with restricting food like this. For them, a focus on energy intake versus energy use or simply on whole foods may be more powerful.
Specific Groups of People
There are also some groups of people who should be careful with a low carb diet.
Pregnant Women. Carbs play an important role in pregnancy, helping to make sure the fetal brain develops effectively. Additionally, too much protein during pregnancy may be damaging to the fetus (15) and some low carb diets (but not all) are also high protein.
A common level of carbs is around 30% during pregnancy. The same is true for anyone trying to get pregnant, as a low carb diet can sometimes impact fertility. Pregnant women should also take advice from their physician about the ideal balance of macronutrients.
Athletes. You can follow a low carb diet and still be an athlete. Some people even do this while on ketosis. But, most athletes will need more carbs to develop muscle and ensure high-quality workouts.
As a ballpark figure, Chris Kresser tends to recommend at least 20% calories from carbs and sometimes suggests as much as 50%. The best solution for you may be different but the key goal is to figure out what works for you.
People with Health Conditions. If you have a serious health condition or are on medication, you need to take care. A low carb diet may have some unexpected outcomes for you and could be risky. It’s important to remain in close contact with your physician if you do try a low carb diet and make sure you’re aware of how your body responds.
The Type of Diet Matters
I’ve been talking about low carb diets in a very general sense, but there is a huge amount of variation.
For example, diets like the Atkins diet and ketosis are extreme examples of low carb diets. These styles require a dramatic change and involve almost completely avoiding carbs.
The radical nature of that change can leave many people feeling bad, especially early on. Still, the style does get easier over time. The idea can also be powerful. Just look at how popular ketosis is these days.
On the other hand, many low carb diets are less extreme.
For example, some people might follow a calorie restricted diet, where they choose fat over carbs as much as possible – but might still consume bread and pasta on occasion.
An alternative would be a liberal version, which Diet Doctor defines as between 50 to 100 grams of carbs each day. This is still low carb compared to the average diet – but it is considerably easier than a ketosis diet, especially for beginners.
It’s also worth pointing out that the research on low carb versus low-fat diets has considered a wide range of different variations of those two diets.
For example, the studies often vary in what percentage of calories come from carbs or fat. Likewise, some studies ensure that both diets provide the same calories while others do not.
This reinforces the idea that people can choose low carb diets that suit their own needs.
Low carb diets are powerful. Many people lose weight through them, gain energy and even resolve health issues.
It’s also clear that low carb diets aren’t for everyone. And honestly, that’s okay.
People are different from each other and there are multiple good ways to lose weight and improve health.
At the end of the day though, both carbohydrates and fats are sources of energy, and neither of them is inherently good or evil. Each group is also complex. For example, some types of fat are healthier than others, and the same is certainly true for carbs and sources of carbs.
Likewise, there are examples of healthy and nutritious food that falls under a low carb diet, and similar examples for a low-fat diet.
Whatever diet approach you take, the idea is to pick one that works for you and works for your lifestyle. There are so many options out there, and some of them might be a natural fit and others simply won’t be.
Low carb diets are often overlooked because people assume that they aren’t healthy or mightn’t be safe. But, the reality is that they can be a very effective diet type.
This style may also be a great idea if other types of diet simply aren’t working.
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