Nutrient Shortfalls on Low-Carb Diets: Which Ones to Watch
Quick answer: Studies of low-carb eating patterns have found them coming up short on some vitamins and minerals, notably thiamine, folate, vitamin C, iron and magnesium in one trial of women on Atkins (Gardner 2010). Potassium is the other one KetoDick flags, because its classic sources are starchy (video lbRPlGZ3Rvw). The common fix is the one he keeps coming back to: spend your carbs on vegetables (video 1vyxuWlxT5M).
On this page
- What the diet studies found
- It isn't only a keto problem
- The shortfalls to watch
- Why the greens stay
- How to cover the gaps
- What the research says
- KetoDick's take
- When to involve your doctor
- Key takeaways
- Related
What the diet studies found
Two studies anchor this.
The A TO Z trial put women on one of several diets, including Atkins. At eight weeks, the Atkins group had shifted toward inadequate intake of thiamine, folate, vitamin C, iron and magnesium (Gardner 2010). That's intake, what people ate, not a blood test showing a deficiency.
A menu-modelling study took the published meal plans of four popular diets, one of them Atkins for Life, and found none met the reference intake for all 27 micronutrients from food alone (Calton 2010).
So the honest summary: a low-carb plan as people tend to eat it can come up short. Nothing in either study says low-carb has to.
It isn't only a keto problem
This matters, because it's easy to read "Atkins group short on five nutrients" as a knock on low-carb in particular.
In the A TO Z trial, the other diets had their own shortfalls (Gardner 2010). In the menu study, none of the four plans covered everything (Calton 2010). And before anyone changes their diet, a large share of US adults already eat less magnesium than the average requirement (Rosanoff 2012).
Any diet that cuts out food groups has gaps to watch. Low-carb's gaps are just in different places.
The shortfalls to watch
| Nutrient | What the sources say | His angle |
|---|---|---|
| Magnesium | Atkins group moved toward inadequacy (Gardner 2010); many US adults already low (Rosanoff 2012) | Leafy greens (video lbRPlGZ3Rvw) |
| Calcium | Not one of the Gardner shortfalls; he counts it as an electrolyte to cover | Leafy greens such as spinach (video 1vyxuWlxT5M) |
| Potassium | Adequate intake 2,600 mg women, 3,400 mg men (NASEM 2019) | Hard on keto because potatoes are the usual source; light salt helps (video lbRPlGZ3Rvw) |
| Vitamin C, folate, thiamine, iron | Atkins group moved toward inadequacy (Gardner 2010) | Greens and a multivitamin backstop (videos 1vyxuWlxT5M, lbRPlGZ3Rvw) |
| Vitamin A | Not named in the studies above | He lists it among what greens bring (video 1vyxuWlxT5M) |
The potassium arithmetic is worth doing once. To get your potassium from potatoes, he points out, you'd blow way past your carbs (video lbRPlGZ3Rvw). That's why he reaches for light salt instead, which is part potassium chloride. See Light Salt and Potassium Chloride.
Why the greens stay
Here's the trap. You start keto, you learn that vegetables have carbs, and you start treating lettuce like the enemy. KetoDick's line for this: people get into keto-flu trouble by avoiding carbs early on and looking at lettuce like it's the devil (from the video lbRPlGZ3Rvw).
His fix is to think of your carb allowance as a budget and spend it well. Many people, he says, spend their 20 g on keto desserts or a few chips, when it should go on vegetables (video 1vyxuWlxT5M). Lettuce and arugula are "pure carbs," in his phrase, but you get a huge volume for very few grams, and greens bring satiety, vitamin A, calcium and magnesium (video 1vyxuWlxT5M).
That's the whole argument in one move. The diet studies say low-carb plans come up short on micronutrients. Vegetables are where many of them live. So the vegetables don't go.
How to cover the gaps
So what you do:
- Spend your carbs on vegetables first. Leafy greens, then other low-carb vegetables. Count them, don't fear them (video 1vyxuWlxT5M).
- Make them taste good. He cooks vegetables in seasoned oil, bacon fat or butter, and hides arugula under steak and gravy (video 1vyxuWlxT5M).
- Salt properly, and use light salt for some of your potassium (video lbRPlGZ3Rvw).
- Once you're fat adapted, a "nutrient loading" day is fine. After about three to five weeks, he'd be comfortable with an occasional higher-carb day, 50 to 100 g, built around a quality salad; he's clear that's not a cheat day (video 1vyxuWlxT5M).
- Treat a multivitamin as a backstop, not a replacement (videos lbRPlGZ3Rvw, UygKGoP_BtA). Whether that does much is covered in Do Multivitamins Actually Work?.
- Watch the packaged "keto" treats. In his beginners' video he suggests limiting net-carb packaged treats to a few items a week (video UygKGoP_BtA). They use carbs you could spend on greens.
He also notes something people find surprising: once you're a few weeks in, cravings for vegetables are probably real needs, not carb addiction (video 1vyxuWlxT5M). Listen to them.
What the research says
- Low-carb intake shortfalls: Atkins group moved toward inadequacy for thiamine, folate, vitamin C, iron and magnesium at 8 weeks; other diets had other shortfalls (Gardner 2010).
- Meal plans: none of four popular plans met all 27 micronutrient reference intakes from food (Calton 2010).
- Baseline magnesium: a large share of the US eats less than the average requirement (Rosanoff 2012).
- Food first: the US Dietary Guidelines say needs should be met mainly from foods and drinks, with supplements useful where needs are hard to meet otherwise (Dietary Guidelines).
- Supplements for prevention: the Task Force calls the evidence on multivitamins insufficient (USPSTF 2022).
What's missing: none of the studies here tested a well-planned, vegetable-heavy keto diet against the reference intakes. So nobody can tell you from this evidence exactly how short a careful keto eater runs. The safe reading is: watch these nutrients, eat your greens.
KetoDick's take
He's said "eat your vegetables" in some form in many of his videos, and by his 2019 rebuttal of a Men's Health article it had become a much blunter version of the same line (video 1JbK1_ClDmY). In 2017 his preferred source for calcium and magnesium was leafy greens, with salt and light salt for sodium and potassium and a multivitamin to cover your bases (video lbRPlGZ3Rvw). His carbs-and-fibre video is built around spending the carb budget on vegetables rather than desserts (video 1vyxuWlxT5M).
Where he and the literature line up: the studies show low-carb plans come up short, and his fix is the food the studies suggest is missing. Where he goes further than the evidence here: the nutrient-loading day is his idea, reasoned from glycogen arithmetic, not something these studies tested.
When to involve your doctor
- Baseline labs before you start, especially if you're older or have health history, so you can compare later (video GojQvo_2GS0). See Blood Tests Before Keto.
- Before potassium or magnesium pills, and with any kidney or heart history (video lbRPlGZ3Rvw).
- Pregnancy or trying to conceive. Folate and iron needs change, and that's a conversation for your doctor before any restricted diet.
- Any history of disordered eating. He says to talk to your therapist and probably your doctor before deliberate restriction (video xyEZL0HuejI).
Key takeaways
- Diet studies found low-carb plans short on thiamine, folate, vitamin C, iron and magnesium.
- Other diets have shortfalls too; it's not unique to keto.
- Potassium is hard on keto because its classic sources are starchy.
- Spend your carbs on vegetables; greens cover several gaps at once.
- A multivitamin is a backstop, not the plan.
- Get baseline labs, and check with your doctor before mineral pills.