Quick answer: Substance use depletes the body in specific ways. Alcohol blocks absorption of B vitamins, opioids slow the gut, and stimulants suppress appetite for weeks at a time. Eating regularly and enough matters more in early recovery than any supplement, and thiamine deficiency after heavy drinking is a genuine medical concern.
Most nutrition advice written for people in recovery reads like it was written for people who are already well. Eat more leafy greens. Drink more water. Try this supplement.
Your body has been through something more specific than that, and what it needs is more specific too. Here is what actually happens physiologically, what the evidence supports, and where the popular advice gets it wrong in ways that matter.
What substance use does to your nutrition
Not all substances deplete you the same way, which is why generic advice misses.
Alcohol does the most nutritional damage, and it does it on several fronts at once. It irritates the stomach and small intestine so that absorption drops. It interferes with how the liver stores and activates vitamins. And it supplies calories with essentially nothing else attached, so appetite falls while intake looks adequate on paper. A 2024 review of nutritional deficiencies in alcohol use disorder found the shortfalls cluster in thiamine, folate, B6, B12, vitamin A and zinc. In alcohol-associated hepatitis, malnutrition is common and tracks with worse outcomes.
Alcohol also loosens the gut lining. Increased intestinal permeability lets bacterial products into the bloodstream and drives gut-derived inflammation, which is part of why people feel systemically unwell well past the last drink.
Opioids cause a different problem. They bind receptors in the nervous system of the gut wall itself, which slows motility and reduces the fluid secreted into the bowel. The result is constipation that does not fade with tolerance the way other opioid effects do. Add nausea and early fullness and people simply eat less.
Stimulants suppress appetite hard, and the weight comes off muscle as well as fat. One study of street-involved youth found crystal methamphetamine use independently associated with being at risk of malnutrition. When appetite returns in early recovery it often returns all at once, which is disorienting if nobody warns you.
B vitamins in alcohol withdrawal, and why thiamine is different
This is the part of recovery nutrition that is genuinely urgent, and it is the part most diet articles skip.
Thiamine is vitamin B1. Your body stores only a few weeks’ worth. Heavy drinking reduces how much you absorb, how much you retain, and how well you convert it to its active form, so stores can run down faster than you would expect.
When thiamine runs out, the brain is affected first. Wernicke encephalopathy is the acute result, and it can show up as confusion, unsteadiness on the feet, or eye movement problems. Often not all three together, which is part of why it gets missed. Untreated it can progress to permanent memory damage, and it is treated with thiamine given by injection or drip rather than by mouth, because absorption cannot be relied on in exactly the people who need it.
One thing worth knowing before you or someone with you is treated: giving glucose to a thiamine-depleted person can precipitate or worsen Wernicke encephalopathy, so thiamine should come first. If someone with a history of heavy drinking is confused, unsteady, or has abnormal eye movements, that is an emergency room visit, not a supplement aisle problem. Call 911 if they are seriously unwell.
The other B vitamins matter too. Thiamine is found in pork, fish, whole grains, legumes and fortified cereals, and folate, B6 and B12 come from a broadly similar list. Food is the right long-term answer. But if you have been drinking heavily and are stopping, this is not a gap to close on your own with a bottle from the pharmacy. Repletion in that window belongs with a clinician who can dose it properly and check what else is low.
What to actually eat in early recovery
The honest version is less complicated than most articles make it.
Eat on a schedule, even when you are not hungry. Appetite signals are unreliable for the first few weeks and waiting for hunger means eating far too little. Three meals with something in between is a reasonable frame, and smaller and more frequent is better than large and occasional if nausea is in play.
Get enough protein. It is the nutrient most often short, and it is what tissue repair and immune function are built from. Eggs, fish, poultry, dairy, beans and lentils all work. If cooking feels impossible, which it often does early on, a carton of milk or a tin of beans is not a failure.
Do not chase percentages. If you are underweight or have been eating erratically, the goal is enough calories and enough protein, not a macronutrient split. That comes later, if at all.
If cooking is the barrier: a week of the same three simple meals beats an ambitious plan you abandon. Batch cooking, tinned fish, frozen vegetables and pre-cut produce all count. Nobody is grading the method.
How much should you drink, and who needs to be careful
You will see a firm number for this almost everywhere. Two litres, three litres, eight glasses. For most healthy adults a number like that is harmless, if not particularly evidence-based.
It is not harmless for everyone reading this page.
If you have alcohol-associated liver disease, your body handles fluid and sodium differently. When fluid builds up in the abdomen, the treatment is restricting sodium, not drinking more water, and when blood sodium runs low, fluid is restricted rather than encouraged. The clinical guidance on managing ascites and hyponatremia in cirrhosis is explicit about this. A generic hydration target aimed at that reader points in the wrong direction.
Get your fluid target from your clinician, not from an article, if you have liver disease of any kind, heart failure, or kidney disease. The same applies if you are on diuretics, or if you have been told your blood sodium is low. For everyone else, thirst plus pale urine is a better everyday guide than a fixed number, and more fluid is needed in heat or with exercise.
Why you suddenly want sugar all the time
This surprises people, and it is real rather than imagined. In early recovery from alcohol use disorder, daily tracking studies show that sweets craving and alcohol craving move together. On the days one is high, so is the other.
What that means practically is less clear than the internet suggests. A 2025 systematic review looking at whether sugar could be used deliberately as part of treatment concluded the evidence is not there yet. So nobody can tell you with confidence that leaning into sweets helps, or that cutting them out helps either.
Reasonable middle ground: if sugar is what is standing between you and drinking this month, it is not the emergency. Deal with it later. What does help now is not arriving at 4pm having eaten nothing since breakfast, because a blood sugar crash and a craving feel almost identical from the inside, and the crash is the one you can prevent.
Digestive problems, and what to do about them
Constipation, nausea, reflux and loose stools are all common in the first weeks. Opioid-related constipation in particular can persist and usually needs treating rather than waiting out, so raise it with your clinician instead of assuming it will settle.
You may have seen the BRAT diet recommended for this, meaning bananas, rice, applesauce and toast. It is not the current advice. It is nutritionally thin, and restricting an already undernourished person to four low-protein foods is the opposite of what recovery needs. Better to eat whatever you tolerate, keep protein in it where you can, and return to normal food as soon as you are able.
Fermented foods like yoghurt, kefir and sauerkraut are fine to include and unlikely to hurt. The evidence that they meaningfully change recovery outcomes is not strong, so treat them as food you might enjoy rather than treatment.
Get seen promptly for vomiting you cannot keep fluids down through, black or bloody stools, severe abdominal pain, yellowing of the skin or eyes, or weight loss that keeps going.
Supplements: what the evidence actually supports
This is where recovery nutrition attracts the most marketing and the least evidence, so it is worth being blunt.
Milk thistle for liver support. Widely recommended, including for alcohol-related liver disease. According to the National Center for Complementary and Integrative Health, trials in liver disease have been conflicting or too limited to draw conclusions, and laboratory effects have not carried through to results in people. It is generally well tolerated. That is not the same as working.
Chromium, magnesium or zinc for cravings. There is no good evidence that any of these reduces cravings. The NIH Office of Dietary Supplements does not support chromium for that use. Correcting a deficiency your clinician has measured is a different matter and can be worth doing. Taking minerals in the hope of blunting cravings is not.
What does have evidence behind it for cravings is medication for alcohol and opioid use disorder. Naltrexone, acamprosate and buprenorphine are all effective and all underused, and no supplement substitutes for them.
Tell whoever prescribes for you about everything you are taking, including anything herbal. Supplements interact with medications, and liver disease narrows the margin further.
When to bring in a professional
Nutrition support in addiction treatment is more available in theory than in practice. Registered Dietitian Nutritionists have a defined role in this work, but surveys of treatment centres have found only a minority actually employ one. So it is often on you to ask.
It is worth asking if you have liver disease, diabetes, an eating disorder alongside substance use, ongoing unintended weight loss, or if you have simply not been able to eat consistently for months.
Blood work is a reasonable starting point rather than guessing. Knowing what is actually low beats supplementing on suspicion.
Talk to a physician about recovery, not just diet
Dr. Meenu Vaid is board certified in Internal Medicine, Infectious Disease and Addiction Medicine, and sees patients in Morgan Hill and by telehealth across California. Nutrition is one piece of a recovery plan. If nobody has looked at the rest of yours, that is a good reason to book.
If you are in crisis or thinking about harming yourself, call or text 988 for the Suicide and Crisis Lifeline. For treatment referrals at any hour, SAMHSA’s free national helpline is 1-800-662-HELP (4357).
Frequently asked questions
Which B vitamins matter most in alcohol withdrawal?
How much water should you drink in recovery?
Do supplements help with cravings?
Does milk thistle protect the liver?
Why do I crave sugar so much in early recovery?
Medically reviewed by Dr. Meenu Vaid, MD, Board-Certified in Internal Medicine, Infectious Disease, and Addiction Medicine. Last clinically reviewed on August 1, 2026.
This article is for general educational purposes only and is not medical advice. Reading it does not create a doctor-patient relationship. For emergencies call 911. For crisis support call or text 988.
