Human beings are an omnivorous species. Our ability to thrive on a diverse array of food options served us extremely well in early human history, contributing in large part to our evolutionary success.
But, in today’s world, we’re faced with an almost unlimited variety of food choices, which creates a dilemma: What should we eat? Of the diverse diets now available, which one should we choose? Which is best for our body and health?
It would take an entire book to fully explore these questions, and for that, we recommend Michael Pollan’s “The Omnivore’s Dilemma”.
But in this guide, we’ll help you to choose the optimal diet for meeting your specific weight loss and health goals.
Macro Diets vs CICO Diets
There are two main categories of diets commonly followed for weight loss.
These are Calories-In / Calories-Out (CICO) and macro-based diets.
CICO diets are based on the theory that health and weight loss can be reduced to a simple formula where: (calories taken in) - (calories expended) = (change in weight).
The idea is that a calorie deficit results in weight loss, a calorie surplus results in weight gain, and that’s all that matters.
For weight loss, individuals following this style of diet typically count their calories from food and track calories expended from exercise in an eﬀort to hit a specific calorie goal each day.
The key here is that in most CICO-style diets, there is no guidance provided on what foods you are eating to get the calories, as long as you remain within your calorie goals.
Now, calories are important, but a CICO-only approach to weight loss -- without providing guidance as to where those calories should come from -- is flawed in that it sees all calories as being equal, and thus all foods as equal.
A macro-based diet understands that all foods are not equal.
There are three types of macronutrients that are present in all foods in diﬀerent ratios: fat, carbohydrates, and protein. And depending on the ratio, diﬀerent foods can have very diﬀerent impacts on your body and metabolism.
Similar to a strictly CICO-based diet, a macro-based diet first decides how many calories you need per day based on your lifestyle and your individual goals. But it then goes further by setting a specific ratio of the three macronutrients (expressed as a percent of total daily calories) as a daily goal. Diﬀerent macro-based diets use diﬀerent specific macro ratios to achieve specific physiological eﬀects in your body.
For example, Keto sets a target macros ratio of 5% carbs, 25% protein, and 70% fat (often written as 5:25:70). The “Zone” diet uses 40% carbs, 30% protein, and 30% fats (40:30:30). The so called “Carnivore” diet is 0% carbs, 25% protein, 75% fat (0:25:75). And the standard “bodybuilding” diet is usually 25% carbs, 40% protein, 35% fat (25:40:35).
In comparison, the “Standard American Diet” is typically around 50% carbs, 20% protein, and 30% fat (50:20:30), give or take.
CICO-style diets treat the human body like a machine with a combustion engine, where eating food is akin to simply “filling the fuel tank”.
Macro-based diets, on the other hand, recognize that human beings are complex omnivorous animals with diverse nutritional needs. With a macro-based diet, the focus is shifted from simply depriving yourself of calories to providing your body with the energy and nutrients it needs to run eﬃciently and to trigger specific physiological changes.
Throughout the remainder of this guide, we’ll explore some of the most popular macro-based diets. We’ll look at the benefits and drawbacks of each, and help you to decide which one might be right for you.
The Ketogenic Diet is perhaps the most well-known macro-based diet. It’s a low-carbohydrate, moderate-protein, high-fat diet that was initially prescribed to children with epilepsy back in the 1920s, and which has become famous over the past two decades as an eﬀective weight loss regime.
The diet recommends a macros ratio of around 70% fat, 25% protein, and 5% carbs. This macros ratio has the eﬀect of putting the body into metabolic Ketosis, which recent research suggests may impart a variety of health benefits. Keto recognizes that all food is definitely NOT equal, and puts a priority on consuming an abundance of healthy fats and oils, non-starchy, nutrient-dense veggies, and organic, free-range meats.
- Weight loss
- Enhanced fat burning
- Appetite suppression
- Increased energy
- Better blood-sugar stability
- May improve medical conditions like diabetes, obesity, high blood pressure, and epilepsy
- May decrease risk factors for heart disease
- Diﬃculty with adherence: Some individuals may find the diet to be too restrictive for their tastes, and find that they’re unable to stick with it long term as a result. But Carb Manager can help!
- There aren’t yet many studies showing the impacts of long-term adherence to the diet
- You may experience Keto flu as you transition into Ketosis
- Could lead to nutrient deficiencies if followed incorrectly
- Contra-indicated for individuals with certain medical conditions
Who is Keto For?
If you’re free from any serious medical conditions and are looking to lose weight and feel better in general without attempting a more extreme diet, Keto may be your best bet. In addition, for those who are diabetic, dealing with PCOS or inflammation, or suﬀer from a health condition that may be improved by a Keto diet, it’s important to discuss Keto with your doctor.
Who is Keto Not For?
While Keto may have a powerful impact on weight loss and a variety of other health conditions, it’s not for everyone. Here’s a list of some conditions that may counter-indicate trying Keto:
- Pyruvate carboxylase deficiency
- Impaired liver function
- Fat metabolism disorders
- Active gallbladder disease
- History of kidney failure or other renal issues
- Gastric bypass surgery
- Whenever in doubt, consult a physician
Carnivore AKA Zero Carb
The most extreme low-carb diet possible, as it involves completely eliminating carbohydrates. On the Carnivore diet, you eat only animal products. Meat, animal fat, and eggs. Some individuals eat dairy (but never milk, as it has carbs); many exclude it completely. Vegetables and other plant-based foods are strictly forbidden. Supplements are usually discouraged because, well, they’re not made of meat.
According to this dietary theory, most of the vitamins and minerals your body needs are found in meat and animal products. For the rest, the theory hypothesizes that your body will adapt so that it no longer needs them.
There are no macronutrient targets to follow, although some people advocate 1:1 for fat:protein.
To ensure that users are getting the full array of nutrients required, many recommend eating liberal quantities of organ meats, such as liver, kidney, bone marrow, and other oﬀal.
Quick note: We know what you’re thinking. But no, this diet probably won’t cause scurvy.
Scurvy came about in the 1800s when sailors subsisted on jerky and other dried meats. Vitamin C is a water-soluble nutrient. The process of dehydrating meats removed Vitamin C from the meat. Advocates of the Carnivorous diet argue that meat that hasn’t been dehydrated contains enough Vitamin C to prevent scurvy.
But on that note, if you do decide to go carnivorous, it may be beneficial to include cod roe, oysters and, again, organ meats as dietary staples as these are relatively high in Vitamin C.
Many of the claimed benefits of the Carnivore diet are the same as those for Keto.
- Weight loss
- Increased testosterone
- Enhanced fat burning
- Appetite suppression
- Increased energy
- Better blood-sugar stability
- Improved medical conditions like diabetes, obesity, high blood pressure, and epilepsy
- Decreased risk factors for heart disease
In addition, the Carnivore diet is extremely simple to follow; as long as you’re only eating animal products, there’s nothing else to think about.
Finally, this diet tends to act as a complete elimination diet for people with multiple sensitivities, as most common “problem foods” are excluded.
- Could cause nutrient deficiencies. Some advocates suggest that your nutritional needs will change when you stop consuming carbohydrates, but no research has been conducted to date, and this claim has yet to be verified.
- Some people report decreased athletic performance
- As with Keto, there’s not a lot of research on the eﬀects of following this diet long term
- Unlike Keto, there’s also not much (or any) research on the eﬀects of following this diet even in the short term
- Doesn’t provide any fiber; may result in digestive diﬃculties
- Environmental impact; meat production is believed to have a high carbon and pollution footprint
- May feel overly restrictive
Who is the Carnivorous Diet For?
Healthy individuals who enjoy experimenting with extreme diets. Those who want or need to try an anti-inflammation elimination diet.
Who is This Diet Not For?
To be completely transparent, it’s not for most people. If you want to try this relatively extreme diet, be sure to do your research and talk to a nutritionally educated physician who is aware of current research, and to follow-up regularly.
No, this doesn’t involve eating bacon that’s been dropped on the floor. “Dirty” Keto means that you’re following the same macronutrient breakdown as standard Keto, but with one key diﬀerence: there is no guidance as to what types of foods the macronutrients come from. As far as “Dirty” Keto is concerned, you can eat as much fast food or processed junk as you want, as long as it fits your macros ratios.
- Super simple; lots of food options
- Cheap; processed and factory-farmed meats are very inexpensive
- Eat all the fast food you want. Just hold the bun, fries, and soda.
- You’ll likely still lose weight as long as you stay in Ketosis and eat at a calorie deficit
Mostly the same as with any diet where you’re eating junk food with low quantities of nutrients.
- Many of the same poor health outcomes as with any diet where you’re eating junk food with low nutrient density
- Skin blemishes
- Exacerbated Keto flu symptoms
- Weight gain after going oﬀ the diet
- Sugar cravings
- Bloating and gut issues
Who is Dirty Keto For?
On a long term basis, the “Dirty” Keto diet should actually be for nobody, due to the inclusion of large amounts of low-quality processed food. However, the “Dirty” Keto diet CAN have its place when you’re in a pinch. Many dieters who normally eat a clean, whole-foods version of Keto, will fall back on “Dirty” Keto when experiencing a really hectic day, finding themselves stuck in an airport, or wanting a rare “cheat” day that won’t throw them out of Ketosis.
This version of Keto involves following the normal, healthy Keto diet, but without formally tracking your macronutrients. Individuals following “Lazy” Keto attempt to just estimate macros in their heads, without logging them anywhere.
- Less time consuming
Many people find themselves accidentally falling out of Ketosis, plateauing in their weight loss, or suﬀering health setbacks, due to poorly estimating their daily macros.
Who is Lazy Keto For?
“Lazy” Keto is best left to advanced Keto dieters who’ve been following Keto for a very long time, have an expert level understanding of the macros ratios for all foods that they’re likely to eat, and have an intuitive feel for what’s going on with their bodies. In addition, if you ARE going to attempt “Lazy” Keto, it’s best done when you’re just maintaining weight rather than trying to lose weight.
Who is it Not For?
- Anyone currently trying to lose weight
- Anyone using Keto to manage a medical condition
- Anyone not meeting the other recommended requirements above
There are many different theories for how to eat when bodybuilding. Bodybuilding diets will be very high in calories and protein intake combined with intense heavy lifting. Bodybuilders have complex diet phases and exercise cycles to reach their specific body-shaping goals. While there are a variety of macros based Bodybuilding diets, a common ratio is 25% carbs, 40% protein, 35% fat (25:40:35).
May help with gaining maximum amount of muscle weight and appearance for a given individual’s genetics when combined with heavy weightlifting.
- Not useful for weight loss
- Not useful for managing medical conditions
- When not combined with heavy weightlifting, will result in weight gain from fat
Who is the Bodybuilding Diet For?
- Those looking to gain large amounts of muscle mass
Who is it Not For?
- Anyone NOT looking to gain large amounts of muscle mass
- Anyone looking to manage a health condition with their diet
LCHF - Low-carb, High Fat (Other Than Keto)
This is actually a category of macro-based diets that recommend low- carb, high fat, and moderate protein intake. Keto is technically LCHF, but not all LCHF diets are Keto.
There’s no precise definition as to what constitutes a LCHF diet. Some nutrition experts consider “low-carb” to be less than 45% of calories from carbs. Others are more strict and consider the limit to be 20% or less of calories from carbs. And of course, certain diets in this category, like Keto or Carnivore, restrict carbs even further.
Regardless, these diets are always lower in carbohydrates and higher in fats than the “Standard American Diet”, which typically includes a ratio of 50% carbs, 20% protein, and 30% fat (50:20:30).
In addition, fat macros vary among diets in this category, and tend to fall somewhere between 50%-70% of calories.
Examples of specific LCHF diets include:
- Low-carb version of Paleo
- Low-carb version of the Mediterranean diet
- Tim Ferris’ “Slow Carb” diet
LCHF may oﬀer many of the same benefits as the Ketogenic diet.
- Weight loss
- Appetite suppression
- Increased blood sugar stability
- Increased energy
- May benefit a variety of health conditions like diabetes, PCOS, high blood pressure, etc.
- In addition, non-Keto LCHF diets are a bit less restrictive, and include many more carbs and food options than Keto itself.
These drawbacks refer to non-Keto LCHF diets.
- LCHF diets that include a ratio of more than about 5% carbs do not put the body into metabolic Ketosis. As we explore in Carb Manager’s Ultimate Guide to Keto, Ketosis comes with its own unique benefits.
- Health benefits may be reduced with increased carb intake.
Research is lacking, but some experts believe that the health benefits of low carb increase the further carbs are restricted, peaking at the Keto target level of 5% of calories from carbs.
- Higher likelihood of carb cravings
- Reduced degree of appetite suppression
- Testing isn’t possible the way it is with Keto; no objective way to tell whether you’re “doing it right”
Who is the LCHF Diet For?
Those who want to get most of the benefits of a low-carb diet, but aren’t able to successfully follow a more restrictive Keto diet.
Who is it not for?
- Those with medical conditions that would counter-indicate a very low-carb diet.
- Those who rely on being in a state of Ketosis to manage a medical condition.
Zone is a relatively balanced diet that advocates for moderately low- carb consumption and moderately high-fat intake. The diet was pioneered by biochemist Barry Sears in his 1995 book "The Zone: A Dietary Road Map", and advocates for a macros ratio of 40% carbs, 30% protein, and 30% fat (40:30:30). Much like standard Keto, the Zone diet recommends a diet of healthy, unprocessed, whole foods.
- Claims to put the body into a metabolic state called “the Zone” which is supposed to be ideal for burning fat
- Claims to control inflammation
- Claims cognitive benefits
- Claims that it prolongs the “healthspan”
- Less restrictive than Keto or many other LCHF diets
- There’s little to no research to back up the claims made about benefits
- In contrast to Ketosis, there’s no way to test for the “Zone” metabolic state; in fact, there’s little evidence that this metabolic state exists
Who is the Zone Diet For?
Those who want the benefits of an all-around healthy, Mediterranean style diet that oﬀers a lot of dietary flexibility.
Who is Zone Not For?
Those who want a diet for weight loss or specific health conditions that has a body of scientific research which may back up its claims.
OMAD is short for “One Meal A Day”. This so called “diet” is more an extreme style of intermittent fasting than it is an actual dietary theory. There are no macros to follow, and OMAD can actually be combined with many of the other diets described in this guide. Dieters following OMAD eat one big meal each day within a one hour window, and engage in a “water fast” for the remaining 23 hours of the day. In fasting terminology, this style of fasting is often written as 23:1 (23 hours fasting, 1 hour eating).
- Many of the same benefits as any style of intermittent fasting
- May induce a state of metabolic hormesis
- May promote and increase levels of autophagy
- You’ll naturally eat fewer calories, which may result in weight loss
- May reduce blood sugar
- May improve insulin function
- Many individuals find that OMAD (or any style of fasting) makes it easier to follow a diet like Keto. No hassles with finding healthy Keto-approved meals at work, on the go, or at restaurants throughout your day because you’re typically only eating at home, in the evening.
- It’s extreme. Your body could have a hard time adjusting.
- If you have any history of an eating disorder, you should avoid this diet, as it may trigger those issues.
- Can be physically uncomfortable eating all of your calories in a single meal
- Extreme fasting may lead to higher cortisol and adrenaline, which can have negative impacts on mental and physical health, as well as body composition.
- If you’re not following Keto along with OMAD, you may experience intense carb cravings during fasting hours.
Who is OMAD For?
This lifestyle is best for:
- Those who have experience with and enjoy fasting, and whose bodies can handle the demands of eating only once per day
- Those who enjoy experimenting with various “life hacks”
Who is OMAD Not For?
- Individuals with current or past eating disorders
- Those who tend to have high cortisol and adrenaline
- People whose body just doesn’t adapt well to extreme fasting
Cyclical Keto Diet (CKD) (AKA Carb Cycling)
This diet is a modified form of the standard Keto diet, and is often utilized by athletes who want to reap the benefits of Keto while enjoying the increased athletic performance from having carbs (glycogen) available to their body as an energy source. In addition, some individuals utilize CKD as a method of giving themselves a Keto “cheat day”.
This variation of Keto involves eating clean carbs one or two days out of the week. The other five or six days, dieters follow a standard Ketogenic diet consisting of the typical 5:25:70 macros ratio.
During the one or two days of carbohydrate ingestion -- also known as the “carb loading” cycle -- dieters are encouraged to eat large amounts of healthy, low-glycemic carbs such as brown rice, potatoes, oatmeal, and whole grains. In addition, it’s equally important that you keep your fat intake low during your carb days to achieve the best results.
- Provides the typical benefits of a Ketogenic diet. These may include benefits of particular interest to athletes, such as increased testosterone levels.
- Allows athletes to maintain optimal performance in athletic activities that require short, intense bursts of energy (weightlifting, sprinting, etc) by providing muscles with glycogen.
- Adds more fiber to the diet, which aids digestion
- Can make the Keto diet easier to stick to in the long term
- It’s possible to inadvertently eat too many calories on carb- loading days, defeating weight loss eﬀorts
- Research on eﬀectiveness for athletes is lacking
- Not recommended for those who rely on Ketosis for their daily health and well-being, such as those using Keto to control diabetes.
Success Tip: If you decide to do CKD, take advantage of the Carb Cycling setting in Carb Manager.
Who is CKD For?
CKD is best for serious athletes or those who feel that their energy and performance suﬀers on a standard Keto diet. It’s probably not worth the hassle or drawbacks for others.
Who is CKD not for?
The Cyclical Ketogenic Diet is not recommended for those who rely on Ketosis for the management of a health condition, such as diabetes.
Putting it All Together
With so many dietary options available for the “omnivorous human animal”, it can feel overwhelming to decide on the diet that’s right for you. The good news is that you’re likely to reap rewards from any steps away from the “Standard American Diet”, as long as your dietary changes include an increase in whole foods and a decrease in carbs. We hope that you found this guide to be a useful resource in choosing a specific diet.
What’s next? To increase your chances of success on the Keto Diet, download the Carb Manager app right now if you haven’t already.
Carb Manager is an all-in-one Keto resource with a built-in macros tracker, Keto recipes, meal plans, an active community, and much more!