Healthy smoothies, raw salads for detox and weight loss? Surgeon warns of kidney stone risk

For years, raw veggies in salads and green smoothies have pretty much ruled the wellness world. Influencers hype about them as “detox miracles,” fitness followers stack their blenders with spinach, kale, berries, nuts, and seeds, and nutrition plans promise glowing skin and weight loss from endless leafy bowls. Somewhere along the line, we all started thinking anything green and raw was automatically healthy.But lately, a lot of doctors are saying, “Hold on. It’s not that simple.”One of them is Dr. Obaidur Rahman, who goes by @drobaid_rahman on Instagram. He recently grabbed everyone’s attention by warning that those healthy smoothies and salads might actually raise your risk for kidney stones, especially if you go overboard on certain ingredients.Turns out, making smoothies full of raw, oxalate-rich greens (like spinach) can mess with your kidneys. Dr. Rahman explains that eating too many raw oxalates lets them bind to calcium and form calcium oxalate stones, the kind that make up most kidney stones. Raw salads and smoothies have benefits (fiber, vitamins), but it’s all about balance.So, what’s the deal with raw veggies in salads?Let’s unpack.In short, not really. The issue isn’t with salads or smoothies themselves — it’s with regularly eating huge amounts of oxalate-heavy foods, especially blended or juiced versions. Scientific research confirms: too much oxalate, combined with dehydration, low calcium, digestive issues, or a history of kidney stones, can put you at risk. In fact, approximately 75% to 80% of kidney stones are composed primarily of calcium oxalate crystals.Now, oxalates are naturally occurring compounds found in many plant foods. They are not inherently dangerous. In fact, many highly nutritious foods contain them. Some top oxalate sources are wellness superstars: spinach, beetroot, chard, almonds, raspberries, cacao, specific seeds, and veggie juices.So, what’s the problem with oxalates, then? The issue emerges when oxalate intake becomes excessively high and combines with other risk factors such as dehydration, low calcium intake, digestive disorders, or a personal history of kidney stones.The irony? A “detox superfood” smoothie can easily contain multiple high-oxalate items, all blended together at levels way higher than you’d eat in a typical meal.Researchers note that vegetable juices, especially, can pack a punch. For example, beetroot juice and some veggie drink mixes rise way above normal oxalate levels. When you juice or blend, you’re eating more veggies faster because nobody sits down to eat half a kilo of raw spinach, but it disappears into a morning smoothie — that’s not a problem.Studies link high dietary oxalate with rising kidney stone risk, especially in people prone to stones. Blending might even make oxalates easier for your body to absorb.Dr. Rahman (and most nutritionists) say the answer is balance — not just “more, more, more.”Here are some smarter ways:In simple terms, it’s never as simple as calling raw vegetables “bad.” Studies show fruits and veggies help prevent kidney stones when you eat them reasonably. A well-balanced diet boosts citrate levels in urine, which protects against stones. Diets rich in a variety of fresh produce are linked to a lower risk.It’s the holy trinity: Variety, moderation, and preparation.For starters, cooking the veggies helps. Boiling can reduce oxalates in veggies by 30% to almost 90%, depending on the plant, which means a plate of steamed spinach is a lot less risky than a giant raw smoothie every morning.Some practical tips:In the end, the bottom line is that salads aren’t the enemy; smoothies aren’t secret health hazards, either. But extremes and obsessions, even with healthy trends, sometimes carry a hidden price.