The slow-carb diet: beans every day, cheat day every week. Half genius, half gym-bro.
Tim Ferriss's 2010 bestseller made beans cool and turned "cheat day" into a lifestyle. There are no trials of the diet itself. Some of its rules are backed by good science anyway. Others are just bro.
The short version
- What it is
- No "white" carbs, no fruit, beans and protein at every meal, the same few meals on repeat, one cheat day a week.
- Good for
- Simple rules, lots of fibre and protein, cutting bread and sugar.
- Bad at
- Evidence. And cheat days can turn into binge days.
- Evidence
- Weak. No trials of the diet, some support for its parts.
- Our take
- Not our plan, but it's a cousin of our Rebel Day idea.
What the slow-carb diet actually is
The slow-carb diet comes from The 4-Hour Body, a 2010 bestseller by American author Tim Ferriss.1 The rules are short:
- No "white" carbohydrates: bread, rice, pasta, potatoes, cereal, anything fried in breadcrumbs.
- Eat the same few meals over and over.
- No fruit (tomatoes and avocado are allowed).
- No sweets.
- Take one day off a week and eat whatever you want.
Every meal is built from three things: protein (eggs, meat, fish), legumes (beans, lentils) and vegetables. It isn't a true low-carb diet, because beans and lentils bring plenty of carbs. They're just slow ones.
How it works in your body
Beans and lentils are full of fibre and protein, which slows down digestion and keeps blood sugar steadier than white bread or rice. Protein at every meal keeps you full. Cutting bread, pastries, sugar and juice removes the foods that are easiest to overeat. Eating the same meals every day removes temptation and decision fatigue.
Put together, most people eat less without counting. That's the whole mechanism. The cheat day is the psychological pressure valve that's supposed to keep you going the other six days.
What you eat, what you don't
Eat
- Eggs, chicken, beef, pork, fish
- Lentils, black beans, pinto beans, chickpeas
- Spinach, broccoli, cauliflower, asparagus, mixed vegetables
- Tomatoes and avocado
- Olive oil, nuts in small amounts
- Water, black coffee, tea
Forget it (six days a week)
- Bread, rice, pasta, potatoes, cereal
- Fruit and fruit juice
- Sugar, sweets, soft drinks
- Desserts and pastries
- Beer and sweet drinks
- Breaded and fried food
A day on the slow-carb diet
- Breakfast: three eggs scrambled with spinach, half a tin of black beans warmed with cumin, a spoon of salsa.
- Lunch: chicken thighs, lentils and roast broccoli with olive oil. Make a big batch: you'll eat it again tomorrow, that's the rule.
- Dinner: chilli con carne without the rice: beef or turkey mince, kidney beans, tomatoes, peppers and onions. Avocado on top.
- Snack, if you must: a handful of almonds or hummus with cucumber.
Filling, cheap and very brown. Nobody does slow-carb for the colours.
Slow-carb in Singapore and in Austria, Germany, Switzerland
Singapore: Indian stalls are your friend: dhal, chana masala and tandoori chicken with vegetables, minus the rice, prata and naan. At yong tau foo, pick tofu, vegetables and eggs, take the clear soup and skip the noodles. Fish balls and fried items usually contain flour, so keep them few. The traps are breakfast ones: kaya toast and the Milo dinosaur.
Austria, Germany, Switzerland: pulses are part of the tradition. Linseneintopf, Bohnensalat and Styrian Käferbohnen with pumpkin-seed oil all fit. Swabian Linsen mit Spätzle fits once you lose the Spätzle. The traps: the Brezel, the Leberkässemmel and the bakery stop on the way to work.
Slow-carb versus paleo
They look like cousins: both cut bread, sugar and processed food, both put protein at the centre. But they disagree on the two things that matter most to the plate. Paleo bans beans and lentils; slow-carb is built on them. Paleo lets you eat fruit; slow-carb bans it six days a week. And paleo has no official cheat day, while slow-carb makes one compulsory. If we had to pick, we'd take slow-carb's beans and paleo's fruit. Our plan does exactly that.
Alcohol on the slow-carb diet
OK, now and then
- A glass of dry red wine with dinner
- Spirits with soda water and lime
Out
- Beer, cider
- Cocktails, liqueurs, sweet wine
- Anything with juice, cola or tonic
- Cheat day as a drinking day
50 Club: one glass of dry red wine with dinner, not every night.
Alcohol pauses fat burning while your liver deals with it: two drinks cut it by about 73% in one study.4 All the details are in our alcohol guide.
What the slow-carb diet is good for, with proof
Beans: a small, real effect
A meta-analysis of 21 trials found that adding about one serving of pulses (beans, lentils, chickpeas) a day led to a small weight loss of about 0.34 kg over around six weeks, even without trying to cut calories.2 Small, but it points the right way, and pulses are cheap, filling and full of fibre.
Low-carb-ish works as well as other diets
Cutting refined carbs works about as well as other approaches. The 2022 Cochrane review found little to no difference in weight between low-carb and balanced diets.3 Translation: slow-carb isn't magic, but its core idea isn't nonsense either.
Simple rules
Protein, beans, vegetables, repeat. You don't need an app. For a lot of people, boring is exactly what works.
The uncomfortable truth
"The cheat day boosts your metabolism." There's no good evidence for that. One day of overeating doesn't meaningfully reset your metabolism. What a cheat day does do is add a lot of calories. A "whatever you want" day can easily wipe out a big chunk of the week's deficit.
"Fruit makes you fat." No. Whole fruit comes with fibre and water and is hard to overeat. Banning it is one of the book's stranger rules. Juice is a different story.
We like the idea of a planned break. We just don't think it should be a day of eating until you feel sick.
The risks
- Binge-style cheat days. For anyone who tends to binge, a weekly "eat everything" day can make it worse.
- Gas and bloating. Beans three times a day is a lot for your gut if it isn't used to it. Increase slowly.
- Missing nutrients. No fruit means less variety in your vitamins and fibre. Lots of different vegetables help.
- Diabetes medication. Big swings between strict days and cheat days make blood sugar control harder. Talk to your doctor.
- Boredom. Same meals every day is efficient. It's also why people quit.
Allergies: watch the staples
| Slow-carb staple | Allergen (EU list of 14)5 | Swap |
|---|---|---|
| Eggs | Eggs | Chicken, fish, tofu |
| Fish | Fish | Chicken, beans |
| Soybeans, edamame | Soy | Lentils, black beans |
| Lupin flour or beans | Lupin | Chickpeas, lentils |
| Nuts | Tree nuts, peanuts | Pumpkin and sunflower seeds |
| Salsa and spice mixes | Sometimes celery, mustard | Fresh tomato, chilli, herbs |
Don't do slow-carb if you…
- have ever had an eating disorder or tend to binge (the cheat day can backfire)
- take insulin or sulfonylureas, without your doctor
- have IBS that flares with beans and lentils
- have kidney disease and have been told to limit protein or potassium
- are pregnant or breastfeeding (fruit and dairy matter)
Healthen me asks about all of these and gives you a different plan if any apply.
How we use slow-carb in your plan
We don't use it as such; it's an info article for us. But the family resemblance is obvious. Our meals are built on protein and vegetables, legumes are welcome, white bread is red-listed, and we have a weekly day off: Rebel Day.
The difference: after Rebel Day comes a fasting day, so the extra calories don't pile up. And fruit stays in. Protein at every meal is a core rule, explained in our high-protein article. For more on planned breaks, see refeeds and diet breaks.
This article is general information, not medical advice. If you have a medical condition or take medication, talk to your doctor before changing how you eat.
Sources
- Ferriss T. The 4-Hour Body. New York: Crown Publishing Group, 2010.
- Kim SJ et al. Effects of dietary pulse consumption on body weight: a systematic review and meta-analysis of randomized controlled trials. American Journal of Clinical Nutrition 2016;103(5):1213–1223. doi.org/10.3945/ajcn.115.124677
- Naude CE et al. Low-carbohydrate versus balanced-carbohydrate diets for reducing weight and cardiovascular risk. Cochrane Database of Systematic Reviews 2022;1:CD013334. doi.org/10.1002/14651858.CD013334.pub2
- Siler SQ, Neese RA, Hellerstein MK. De novo lipogenesis, lipid kinetics, and whole-body lipid balances in humans after acute alcohol consumption. American Journal of Clinical Nutrition 1999;70(5):928–936. pubmed.ncbi.nlm.nih.gov/10539756
- Regulation (EU) No 1169/2011 on food information to consumers, Annex II (the 14 allergens). eur-lex.europa.eu/eli/reg/2011/1169/oj