Low-carb diets like keto and paleo have become extremely popular in the early 21st century. They’re far from the only low-carb diet options you can follow, however.
Some believe that low-carbohydrate eating was “discovered” by Dr. Robert Atkins, developer of the Atkins diet plan in the mid-20th century. But eating plans which are low in carbohydrates have actually been used for medical and weight-reduction purposes since the 19th century. It’s even been documented that Greek Olympic athletes ate low-carbohydrate diets to improve their performances in the 8th century B.C. (1)
And while its basis is archeological evidence rather than documented proof, the Paleo diet (often called the paleolithic diet or caveman diet) is designed to replicate the low-carb meals believed to be eaten by our ancestors well over 10,000 years ago. (2)
What’s the main difference between all of those diets? Generally speaking, it’s the maximum carb intake you’re allowed on the diet. The diets usually recommend different dietary balances between the three macronutrient groups: carbs, fat and protein.
We’ll take a deeper dive into the low-carb diets you can choose from and what you can eat on them – after first looking at the history of these diets, and why they’re so effective for those who want (or need) to lose weight.
The History of Low-Carb Diets
The Banting-Harvey Diet
The first detailed use of a low-carbohydrate was in 1862, when a grossly overweight Victorian-era undertaker named Banting started to have trouble hearing. He saw an ear, nose and throat specialist who told him to lose weight by avoiding sugar, starches, potatoes and beer.
Banting’s weight dropped, his hearing returned – and he ended up writing up his experience in a 1863 pamphlet called Letter on Corpulence. Banting continued to promote low-carb eating throughout the rest of his life. (3)
Low-Carb Diets and Childhood Epilepsy
In the early 1920s, doctors were searching for a treatment for epileptic children who didn’t respond to conventional treatments of the day. They discovered that fasting helped, so they developed a low-carbohydrate diet quite similar to today’s ketogenic diet which was able to dramatically the incidence of seizures.
When better medical treatments were found, the keto diet was largely abandoned as a standard childhood epilepsy treatment. With the decades-later resurgence of interest in low-carb diets – and a greater base of knowledge – it is once again being used to treat some cases of epilepsy in both children and adults. (4)
The 1940s and 1950s: Evidence Grows
Research and experimentation continued to show the benefits of a low-carb diet in the mid-20th century.
The DuPont diet, focusing on meat and fat as the backbones of a weight-loss meal plan, was developed for executives at that company. The eating plan was published in Holiday magazine in 1950. (5)
In the late 1950s, a doctor who ran the first obesity clinic in Britain made the same case and published Eat Fat and Grow Slim. The book put forward the hypothesis that some people’s inability to process carbohydrates was the reason they couldn’t lose weight. It was the first time the concept of metabolic syndrome was discussed in public. (6)
The 1960s and 1970s: The First Glory Age of Low-Carb Eating
Two landmark low-carbohydrate weight loss diets came to prominence in this period.
Dr. Irwin Stillman (together with Samm Sinclair Baker, perhaps better known as one of the inventors of Miracle-Gro) published The Doctor’s Quick Weight Loss Guide in 1967. The Stillman diet plan was a restricted-carbohydrate, high-protein diet for weight loss. It also advised eating no fat, which led many physicians and users to condemn the eating plan for causing fatigue, nausea and increases in cholesterol. It was a quite-popular fad diet of the time, though. (7)
And of course the landmark Atkins diet, published in 1972 in Dr. Atkins’ Diet Revolution, was the eating plan that brought low-carb dieting its greatest popularity of the mid-20th century. It was a diet that was high-protein and higher-fat than Stillman’s, so Atkins believed it wouldn’t cause some of the issues posed by the Stillman diet.
Even so, it was generally viewed as a fad diet and fell out of favor relatively quickly – but found a second life when Atkins published an updated version called The New Diet Revolution in the 1990s, and began selling complementary diet products. The diet remained popular in the late 20th and early 21st century, but many doctors still criticized it and it was overtaken in popularity by more recent theories and eating plans. (8)
Ironically, Atkins was found to have high blood pressure, congestive heart failure and a history of heart attack after his death from a fall in 2003.
The “New” Glory Age Of Low-Carb Eating
Low-fat diets were all the rage in the latter stages of the 20th century, embraced by many members of the medical establishment as well as the government, the media – and dieters. Over time, however, it was realized that since those diets primarily replaced fat with carbs, they didn’t improve heart health by lowering cholesterol. Instead they apparently increased cardiovascular risks. Just as telling, they often weren’t effective for weight loss. (9)
That’s why in the late 1990s and early 2000s, low-carbohydrate diet plans began attracting new attention. The new wave began with the Zone diet (which was only a moderate-carb diet), the paleo diet mentioned earlier, and the South Beach diet (which starts out low-carb and then relaxes restrictions after a month). The 1997 film First Do No Harm, which focused on the keto diet’s continued ability to treat childhood epilepsy, also elevated interest in low-carb eating. (10)
As the 21st century progressed, the number of low-carb eating plans soared. They included the “modified” Atkins diet, the Dukan diet, the bulletproof diet, the LCHF (low-carb, high-fat) diet, the Whole30 diet, and a number of others. And the keto diet, still around throughout that time, regained enormous popularity.
All of those diets vary in their rules governing acceptable food groups, the “proper” amount of carbs to be consumed each day, and how long the eating plan should be followed. However, they’re all based on the same basic scientific principles.
How Low-Carb Diets Work
There’s very little doubt that low-carbohydrate diets are effective, at least in the short term. A survey of research shows that the average patient on a low-carb eating plan loses between three and 30 pounds of body weight, and between one and four inches of waist size. (11)
Low-carb diets also have been shown to provide enormous health benefits. They lower blood sugar levels, triglycerides and blood pressure, while increasing good cholesterol levels and insulin resistance, all risk factors for heart disease. And they’re particularly effective for those with type 2 diabetes. (12)(13)(14)
But why do they work so well?
It’s well-known that a keto diet works its wonders by lowering carbohydrate intake so much that the body enters a metabolic state known as ketosis. In that state, it burns body fat to produce “ketones” to be used as an energy source instead of dietary carbohydrates. That’s believed to be the primary reason the ketogenic diet is so effective. (15)
Many low-carb diets don’t restrict carbs enough for the body to enter ketosis, though, so there has to be more to the story than just ketosis. Not all experts fully agree on the mechanisms, but a number of factors are believed to contribute to weight loss.
- Initial weight loss: The body normally stores a lot of water, particularly in the muscles and the liver. Much of that water – and its weight – is released during the first two weeks of a low-carb diet. There are two reasons for that. When carbs are limited, the body starts utilizing stored sugar known as glycogen; glycogen binds to water, so when glycogen is burned, that water is freed and eliminated. Additionally, eating low-carb diets lowers the body’s insulin levels (16), releasing sodium which carries water with it when eliminated from the body.
- Lower insulin levels: We’ve just mentioned this effect of low-carb eating. And some claim that insulin “locks” fat so it can’t be burned for weight loss, meaning that having less insulin in the body “unlocks” that fat. This theory is controversial, but possible. (17)
- Higher protein consumption: In most low-carbohydrate diets carbs are replaced by protein, consumption of which has been shown to increase the body’s metabolism. A higher metabolism leads to more energy expenditure, so more fat has to be burned to supply that energy. More protein also increases satiety (the feeling of being full), so appetite declines and people eat less food. (18)
- Less junk food: When carb intake is lowered, sugar and starches are virtually eliminated from the diet. In turn, that eliminates foods like candy, bakery goods and junk food. And studies have shown those types of foods stimulate the “reward” center in the brain, causing people to eat more of them. A diet with less variety lowers the brain’s desire to eat, and eliminating the calorie intake associated with junk food certainly helps with weight loss. (19)
Whatever the underlying causes, low-carbohydrate diets have been repeatedly been shown to lead to fat loss and other health benefits over the short-term. (Their long-term viability without causing side effects has been questioned). Finding a balance between a diet that provides those benefits – and one you’ll be able to follow without cheating too much – is the big challenge facing anyone considering going low-carb.
Types of Low-Carb Diets
The basics of low-carb diets are similar. Sugars, starches and most grains are generally eliminated from the diet, replaced by healthy and unprocessed whole foods. Almost all proteins, most vegetables, some fruits and healthy fats form the basis of a low-carbohydrate diet. We’ll take a closer look shortly.
The specifics of any low-carb diet will be a major factor in how “successful” the diet will be for the person trying to follow it. And as we’ve mentioned, there are a lot of choices. Here’s a quick summary of the ones which are most popular.
- Keto: Only 5-10% of your diet comes from carbs, with 20-25% from protein and 70-80% from fat. There are different “flavors” of keto, but the standard ketogenic diet suggests eating no more than 25-50 grams of net carbs (total carbs minus fiber and sugar alcohols) on any given day.
- Atkins: The currently-used version of Atkins breaks the eating plan into four phases. It starts with 20-25 net grams of carbs limited to proteins, greens, cheese, and nuts and seeds. From there you gradually increase carb consumption by adding in vegetables, legumes, some fruits, and eventually whole grains. There’s also an “Eco-Atkins” version which is a vegetarian, high-fat diet.
- Dukan: Like Atkins, the Dukan diet has four phases and you start with a choice of just 68 proteins and nothing else. Gradually, 32 non-starchy vegetables, and then more starches, are added into the allowable food list.
- South Beach: The modern South Beach diet has three phases, but no strict limits on carb or calorie consumption. Instead it starts with a focus on proteins, slowly adds healthy carbs, and finally remains focused on protein as the primary macronutrient.
- Paleo: Based more on a philosophy than macro guidelines, the paleo diet is designed to mimic what cavemen ate. Our ancestors didn’t have access to sugars and grains, so they’re not allowed today either. Animal products and plants are the foundation of this diet, and there are no restrictions on the starchy vegetables which were available to cavemen.
- LCHF: The Scandinavian low-carb, high-fat diet is also based on a philosophy (“health”) rather than counting carbs. In a nutshell, processed foods, starchy vegetables and fruits that are high in sugar are all off-limits.
- Whole30: This diet only lasts 30 days, during which you’re only allowed to eat meat, fish and seafood, eggs, fats, vegetables and fruits. It also prohibits foods that imitate processed foods (like low-carb treats).
That’s a lot of choice, and there are even more possibilities like the low-carb Mediterranean diet, the slow-carb diet, the zero-carb diet and others. They’re basically the same in one important way, though: they eliminate unhealthy carbohydrates. What does that look like in practice? Read on.
Low-Carb Diet Foods
Before we get started, it’s worth repeating: the food choices that you’re “allowed” will vary with the type of low-carbohydrate diet you decide to follow. This rundown, however, is a good starting point for those who are thinking about taking the low-carb plunge.
What You Shouldn’t Eat
Ditch the packaged, frozen and prepared foods, as well as take-out and fast food delivery. You’ll be eating healthy, “real” food instead.
You’ll also be avoiding sugar (and foods that contain added sugar). That not only includes the obvious stuff like soda, fruit juice, cake, cookies and ice cream, but many fruits that are high in sugar like grapes, apples, pineapple and bananas. Some sauces and condiments such as ketchup, jam and barbeque sauce are usually on the “bad” list, too.
The other major categories that are off-limits are grains and starches. You normally think about bread, rice and pasta as high-carbohydrate foods, but vegetables like potatoes and corn are loaded with carbs as well. The rule-of-thumb is that veggies that grow above ground are fine but those which grow below ground aren’t; there are exceptions, though. A subcategory is legumes (primarily beans, peas and lentils), which are all carb-heavy.
Low-carb diets generally encourage you to eat a lot of fat, but some fats are much better than others. The ones to definitely avoid are trans fats, and on most low-carb diets, saturated fats should only be eaten in moderation. Oh, and before we forget, beer and many alcoholic drinks (usually, the ones mixed with juices or sodas) can be problematic as well.
Some foods are on the border line, based on the low-carb diet you’re following. For example, sweet potatoes are fine for paleo, but not on most other low-carbohydrate diets. Whole-grains are allowed in later stages of Atkins, but never on keto. Each diet will have its own specific list of foods to avoid.
What You Can Eat
Don’t worry – that still leaves a lot of great low-carb foods to put onto your shopping list.
- Proteins: Most low-carbohydrate diets aren’t exactly “high-protein” diets. In fact, too much protein can kick you out of ketosis and even cause weight gain if you’re on a keto diet. But low-carb dieters are encouraged to keep protein intake relatively high, because it keeps you satisfied and staves off hunger pangs. And almost every type of protein (including eggs) is low in carbs, as long as it isn’t processed, breaded or coated with carb-laden sauce. It’s healthiest if meats are grass-fed and pastured, poultry has been raised free-range or fish are wild-caught, and fatty cuts of meat or fish rich in Omega-3 fatty acids are best.
- Vegetables and fruits: Vegetables are one of the keys to any low-carb diet. The ones that grow above ground are usually lowest in carbohydrates, although some (like Brussels sprouts) should only be eaten in moderation. Think leafy greens, cauliflower, avocado, cucumber, zucchini and asparagus. Allowable fruits really depend on the version of low-carb that you follow, but the best choices are berries, watermelon and peaches (again, in moderation).
- Dairy: This is a difficult category to summarize in a paragraph. Butter and heavy cream are encouraged on keto, but discouraged on many other low-carb diets. The same goes for full-fat or low-fat milk (fine for some, not for others) as well as different types of cheeses. The bottom line: you’ll be able to eat some dairy products but not others.
- Fats: Your fat intake should always be high on a low-carb diet, but that means eating healthy fats and not trans fats. Extra-virgin olive oil, avocado oil and coconut oil are among the unsaturated fats which are great choices; butter is better for some types of low-carb diets (hello, keto!) than others. Ghee and lard shouldn’t be ignored, nor should nuts and seeds, most of which are excellent sources of protein as well as fat.
- Spices and condiments: Nearly all spices are great for low-carb diets, and homemade condiments (without added sugar) can make the difference between a routine low-carb meal and a yummy one. Most low-carbohydrate diets forbid sugar, but Stevia is an excellent substitute for cooking.
- Beverages: Sadly, most beverages that aren’t water, or black coffee or tea, contain added sugar. If you want milk but it’s not allowed on your diet, most unsweetened nut milks are. Wine and most spirits are fine in moderation. What about sugar-free soda? It’s OK on some low-carb diets, but usually not recommended because diet drinks have the nasty habit of making you crave more.