Plans for Your Body · Food & fasting
The low-carb plan
Low-carb done right is mostly real food.
The goal: Low-carb works by lowering the insulin that keeps fat locked away. Check your medications first, cut sugar and refined starch, build meals on protein, vegetables and natural fats, pick a carb level you can keep, and retest your blood sugar, insulin and ApoB at 3–6 months. If LDL climbs, adjust your fats.
Low-carb has a reputation problem: bacon piles, “keto” cookies, and a lipid panel nobody checked. Done properly, it’s simpler and duller than that. Take out the sugar and refined starch, eat real protein, vegetables and good fats, and measure what happens. This plan gets you there without the mistakes that give it a bad name.
- CheckDiabetes and blood-pressure medications · pregnancy · kidney disease
- MeasureHbA1c · fasting insulin · lipid panel with ApoB · waist
- ChangeCut sugar and starch · protein and vegetables first · olive oil, nuts, fish
- RetestAt 3–6 months: blood sugar, insulin, ApoB
Most people do low-carb as a fad. This does it as a plan.
Not medical advice
Discuss everything here with a medical doctor before acting on it — supplements included. Your doctor has your bloodwork and history. We have neither.
02 Why it matters
Your diet is mostly sugar, even if it doesn’t taste sweet.
The default
Toast, cereal, sandwiches, pasta, rice, crackers, juice. Refined starch digests into glucose fast, and insulin rises to handle it, several times a day. If you’re insulin resistant, your body has to work harder every time.
The evidence
In a pooled analysis of trials in type 2 diabetes, low-carb diets got 57% of people under the remission line (HbA1c below 6.5%) at six months, against 31% on comparison diets. That count allowed medication; remission without any diabetes drugs was much rarer, with no clear difference between diets. Diabetes Canada now lists low and very-low-carb eating as a healthy option for adults with diabetes.
The catch
Remission data past a year is thin, most of the benefit had faded by 12 months in pooled trials, and many people drift back. In some people LDL and ApoB rise. And if you take diabetes medication, cutting carbs without your doctor can cause dangerous lows.
Knowing why low-carb works tells you how to do it safely.
03 How it works
Carbs drive insulin. Insulin decides where the fuel goes.
Every meal raises blood sugar and insulin; refined carbohydrates raise them most. David Ludwig’s carbohydrate-insulin model argues that high insulin pushes fuel into fat cells and leaves the rest of the body short, so you get hungry again. Lower the carbs and insulin falls, stored fat becomes available, and hunger quiets down.
- Insulin
- Insulin resistance sits underneath type 2 diabetes, fatty liver, high triglycerides and more. Jeff Volek and Stephen Phinney, who have studied carbohydrate restriction for decades, argue that for people with it, carbohydrate intolerance is the problem, and cutting carbs is one of the most direct ways to lower insulin.
- Low-carb
- In the research, under 130 g of carbohydrate a day, or under about 26% of calories.
- Very low-carb (keto)
- Under about 10% of calories, often under 50 g a day. Enough to make the liver produce ketones. Stricter, faster, harder to keep, and more likely to need medication changes. Phinney and Volek call the body’s shift to running mainly on fat “keto-adaptation”; it takes a few weeks, which is why the first fortnight feels worst.
- Triglycerides
- Usually the first number to fall: the liver makes them from surplus carbohydrate.
- LDL and ApoB
- The wildcard. Most people’s are flat or slightly lower; some people’s rise sharply, especially on diets heavy in butter and fatty meat. That’s why you measure.
04 The steps
Check. Cut the starch. Build on real food. Retest at 3–6 months.
Check first · Before day 1
Cutting carbs works fast. So do the side effects of medication.
- Diabetes medicationsdoctor first
Insulin and sulfonylureas can drop your blood sugar too low once carbs fall. SGLT2 inhibitors (the “-gliflozin” drugs) combined with very low-carb eating raise the risk of ketoacidosis, even at normal blood sugar. Talk to your doctor before you start; never adjust doses yourself.
- Blood-pressure medicationswatch for dizziness
Low-carb eating sheds water and salt in the first weeks, and blood pressure often falls. If you feel light-headed, tell your doctor: your pills may need changing.
- Who should waitdoctor first
Type 1 diabetes, pregnancy or breastfeeding, kidney disease, a history of eating disorders, or gallbladder disease.
Measure · Week 0
Get a baseline worth comparing against.
- HbA1cthree-month average
The number that tells you whether this is working for blood sugar.
- Fasting insulin and glucosemorning, after an overnight fast
Together they give HOMA-IR, a simple insulin-resistance score. Fasting insulin often isn’t covered in Canada. It’s cheap to pay for.
- Lipid panel with ApoBask for ApoB
Triglycerides, HDL, LDL and ApoB. ApoB is the one to watch on low-carb: it’s how you catch the people whose particles rise.
- Waisttape measure
Measure at the belly button. More than half your height points to visceral fat.
- Continuous glucose monitortwo weeks
A small sensor on your arm for 14 days shows which meals spike you, how high, and for how long. Repeat every 4–6 months to see the trend. It shows you which carbs spike you and which don’t, so you cut the right ones.
Change the inputs · Months 1–6
Take out the starch. Put back real food.
- Sugar and refined carbscut hard
Sugar, sweet drinks, juice, white flour and most packaged snacks. The fastest lever on insulin, blood sugar and triglycerides. This is low-carb. Bread, pasta, rice, cereal, potatoes and crackers go next, or shrink to a side.
- Real foodprotein first
Build meals on protein, vegetables and natural fats: fish, meat, eggs, dairy, legumes, nuts. Protein and fibre keep you full and flatten glucose spikes. Protein first, then vegetables. Low-carb isn’t a licence for unlimited fat: eat enough to be full, not more.
- Fats to cook witholive oil first
Extra-virgin olive oil, avocado and its oil, nuts, oily fish. Olive oil has the strongest trial evidence: in PREDIMED, a Mediterranean diet with extra olive oil cut heart attacks and strokes. This is how you keep ApoB in check. Lean on olive oil, avocado, nuts and fish; go easy on butter, cream and fatty processed meat.
- Vegetables and fibremost of the plate
Leafy greens, cruciferous vegetables, peppers, mushrooms, legumes in modest amounts, berries. Low-carb with no fibre is how people end up constipated and miserable.
- Pick your levelstart moderate
Under 130 g a day is low-carb; under about 50 g is keto. Start by cutting sugar and refined starch. Go stricter only if you need faster blood-sugar change, and only with your doctor involved if you take medication.
- Salt and waterfirst two weeks
Headaches, fatigue and cramps early on (“keto flu”) are mostly lost water and salt. Phinney and Volek treat enough sodium as part of a “well-formulated” ketogenic diet, not an afterthought. Drink water, salt your food. If you have high blood pressure or heart or kidney disease, ask your doctor first.
- Trainingstrength 2–3×/week, cardio 150+ min/week
Lift, and walk briskly or cycle most days. Muscle is where most of a meal’s glucose ends up, so more muscle means more room for it. Cardio makes that muscle more sensitive to insulin.
- Sleep7+ hours
One short night measurably worsens insulin sensitivity, blood sugar and appetite the next day. The cheapest part of the protocol, and the most skipped.
- Alcoholnone while fixing the numbers
It goes straight to the liver, raises triglycerides and adds to liver fat. Less is better; none is best while you’re fixing the numbers.
Pairs with fasting
Low-carb makes fasting easier, because hunger is lower. If you add an eating window or longer fasts, read the fasting-safety rules first, and tell your doctor if you take any medication.
Retest · Months 3–6
Compare. Then adjust.
- Same testssame lab
HbA1c, fasting insulin, lipid panel with ApoB, waist. On a normal eating day.
- If ApoB or LDL rosechange the fat, not the plan
Swap butter, cream and fatty meat for olive oil, nuts, avocado and fish, add fibre, and retest. If it stays high, take it to your doctor.
- If you’ve stalledcheck the basics
Low-carb snacks, “keto” treats, nuts by the bag and creamy coffee add up. Back to protein and vegetables.
- If the numbers won’t moveyour doctor
Take the before-and-after numbers to your doctor. Whether you need medication is their call. Needing it isn’t failure.
05 The rules
Short list. No exceptions.
Choose
- Protein and vegetables at every meal
- Olive oil, avocado, nuts and oily fish for fat
- Whole foods with a short ingredient list
- A carb level you can keep for a year
Avoid
- Sugar, juice, white flour, and most packaged snacks
- “Keto” cookies, bars and treats
- Building every meal on butter, cream and processed meat
- Cutting carbs on insulin or an SGLT2 inhibitor without your doctor
Non-negotiables
- Talk to a medical doctor first if you take any diabetes or blood-pressure medication.
- Never change a medication dose yourself.
- Measure ApoB before and after.
- Eat vegetables. Lots.
06 Checkpoints
What to track, and what good looks like.
Your doctor sets your targets. These are common reference points.
| What | Target | How and when |
|---|---|---|
| HbA1c | <6.0% (Canada) · <5.7% (US), and falling | Every 3–6 months. Under 6.5% without diabetes medication is the usual remission line. |
| HOMA-IR | Under ~1.0 is ideal; over ~2.5 suggests insulin resistance | Fasting glucose (mmol/L) × fasting insulin (µU/mL) ÷ 22.5. |
| Triglycerides | <1.7 mmol/L (150 mg/dL); <1.1 (100) is optimal | Lipid panel. Usually falls within weeks. |
| ApoB | <0.9 g/L (90 mg/dL) for most; lower if high risk | Before and at 3–6 months. If it rises, adjust your fats and retest. |
| Waist-to-height | <0.5 | Waist at the belly button divided by height. Monthly. |
| Blood pressure | Your doctor’s target | Home cuff. Track it if you take blood-pressure pills: it may fall. |
Converted values are rounded. Ketone meters are optional. You don’t need to be “in ketosis” for low-carb to work.
07 Where experts disagree
Where the experts don’t agree.
Everyone agrees that less sugar and refined starch is good. The fights are about whether carbs matter more than calories, whether low-carb beats low-fat, and what to do about LDL.
Is it the insulin, or the calories?
Carbohydrate-insulin model: Ludwig
High-carb diets raise insulin, trap fuel in fat cells and drive hunger. In Ludwig’s feeding trial, people burned about 200 more calories a day on low-carb while maintaining weight loss.
Energy balance: Hall
Calories decide body fat. In his 2021 inpatient trial, people left to eat as much as they liked ate several hundred fewer calories a day on a low-fat, plant-based diet than on a ketogenic one, even though insulin was higher, which the insulin model doesn’t predict.
Our read Unsettled. For blood sugar and insulin, low-carb clearly wins. For weight, the best diet is the one that makes you eat less without a fight, and for many people that’s low-carb.
Does low-carb beat low-fat?
Low-carb: Diabetes Canada, Goldenberg et al.
For people with diabetes, low-carb diets improve HbA1c and remission rates and can cut medication, at least in the first six to twelve months.
Equal: Gardner (DIETFITS)
In 609 adults without diabetes, a healthy low-carb and a healthy low-fat diet lost about the same weight over a year. Insulin levels at the start didn’t predict who did better. Quality mattered more than ratio.
Our read With diabetes or insulin resistance, low-carb has the edge on blood sugar. Without them, both work if they’re built on real food. Pick the one you’ll keep.
Can it last beyond a year?
With support: Volek, Phinney (Virta trial)
In their two-year trial of a ketogenic diet with remote coaching, about three-quarters of people with type 2 diabetes were still enrolled, HbA1c stayed lower, and most of those who started on insulin cut or stopped it. About half of those still in at two years met the trial’s remission criteria.
Sceptics: pooled trials, including Goldenberg et al.
That trial wasn’t randomized, was run by the company selling the program, and counted remission among people who stayed. In randomized trials, most of low-carb’s advantage had faded by 12 months.
Our read It can last, but rarely without ongoing support, and only for the people who keep doing it. Plan for the long haul: a level you can keep, a doctor checking your medication, and someone to answer to.
Should you worry if LDL goes up?
Lean mass hyper-responder researchers: Norwitz, Feldman
Some lean, metabolically healthy people see LDL soar on low-carb diets. Their 2024 study found no more plaque than in matched controls.
Most lipid specialists
That study was small and short compared with how plaque develops. LDL also rose on the low-carb arm of DIETFITS, and ApoB particles cause plaque whatever your insulin is doing.
Our read Measure ApoB. If it rises, shift your fats toward olive oil, nuts and fish and retest. If it stays high, it needs dealing with, however good your blood sugar looks.
08 Limits
What no plan fixes.
It doesn’t last if you don’t
Low-carb works while you’re doing it. Go back to the old diet and the blood sugar and the weight come back too. Choose a level you can live with, not the strictest one.
Medication is your doctor’s job
If you’re on insulin, a sulfonylurea or an SGLT2 inhibitor, changing your diet changes your medication needs. That’s not optional, and it’s not something to figure out alone.
Genes and lipids
Some people’s LDL and ApoB rise sharply on low-carb, and familial cholesterol problems don’t respond to diet. If yours does, your doctor’s plan comes first.
The plan lowers the insulin. It doesn’t replace your doctor or your lipid panel.
09 Resources
Worth your time.
Always Hungry?
Ludwig’s case that hunger, not willpower, is the problem, and that cutting refined carbs fixes it.
The Art and Science of Low Carbohydrate Living
The practical manual for doing low-carb and keto properly: protein, fats, salt, keto-adaptation, and what to watch.
Long-term effects of a novel continuous remote care intervention including nutritional ketosis for the management of type 2 diabetes
The two-year results of the Virta trial. Read it with its limits in mind: non-randomized, company-run.
The carbohydrate-insulin model: a physiological perspective on the obesity pandemic
The full scientific argument for why carbs, through insulin, drive weight gain.
Low carbohydrate diets for adults with diabetes: summary
Where Canada’s diabetes body stands, including the medication cautions.
10 Questions
Questions, answered plainly.
How many carbs is low-carb?
In the research, under 130 g a day, or about 26% of calories. Very low-carb, or keto, is under about 10% of calories, often under 50 g a day. Most people do well somewhere between.
Is keto better than ordinary low-carb?
It moves blood sugar faster, but it’s harder to keep and more likely to need medication changes. Start with cutting sugar and refined starch; go stricter only if you need to. Volek and Phinney’s two-year results are the best case for keto, and they came with intensive remote coaching.
Will low-carb raise my cholesterol?
Triglycerides usually fall and HDL rises. LDL and ApoB are flat or slightly lower for many people and rise sharply in some. Measure before and after, and adjust your fats if needed.
What is the keto flu?
Headache, tiredness and cramps in the first week or two, mostly from losing water and salt. Drink water and salt your food, unless your doctor has told you to limit salt.
Can I eat fruit on low-carb?
Berries, yes. Larger amounts of sweeter fruit depend on how strict you go. Juice and dried fruit, no.
Is low-carb safe with diabetes?
Diabetes Canada says it can be a healthy option, with your healthcare team involved. If you take insulin, a sulfonylurea or an SGLT2 inhibitor, your doctor has to adjust your treatment first.
11 Sources
Where this comes from.
Experts drawn on
- David Ludwig, MD, PhD — Endocrinologist, Boston Children’s Hospital and Harvard. Lead author of the carbohydrate-insulin model; author of Always Hungry?
- Jeff Volek, PhD, RD — Professor of human sciences, Ohio State University. Dietitian-scientist; decades of trials on ketogenic diets and insulin resistance. Co-author of The Art and Science of Low Carbohydrate Living.
- Stephen Phinney, MD, PhD — Physician-scientist, professor emeritus of medicine, UC Davis. Studied keto-adaptation since the 1980s; co-author of The Art and Science of Low Carbohydrate Living.
- Kevin Hall, PhD — Metabolism researcher. Ran the NIH inpatient trials testing low-carb against low-fat and ultra-processed food.
- Christopher Gardner, PhD — Nutrition scientist, Stanford. Led the DIETFITS trial.
Sources
- Diabetes Canada position statement on low-carbohydrate diets for adults with diabetes: a rapid review (summary). Diabetes Canada, 2020.
- Efficacy and safety of low and very low carbohydrate diets for type 2 diabetes remission: systematic review and meta-analysis. BMJ, 2021.
- The carbohydrate-insulin model: a physiological perspective on the obesity pandemic. American Journal of Clinical Nutrition, 2021.
- Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial. BMJ, 2018.
- Effect of a plant-based, low-fat diet versus an animal-based, ketogenic diet on ad libitum energy intake (NIH summary). National Institutes of Health, 2021.
- Effect of low-fat vs low-carbohydrate diet on 12-month weight loss in overweight adults (DIETFITS). JAMA, 2018.
- Long-term effects of a novel continuous remote care intervention including nutritional ketosis for the management of type 2 diabetes: a 2-year non-randomized clinical trial. Frontiers in Endocrinology, 2019.
- Carbohydrate restriction-induced elevations in LDL-C and atherosclerosis: the KETO trial. JACC: Advances, 2024.
Not medical advice
Discuss everything here with a medical doctor before acting on it — supplements included. Your doctor has your bloodwork and history. We have neither.