Helpful Health Hack or Overhyped Myth?
By Jamie Bussin
In an era of ever-evolving dietary trends, one that continues to spark curiosity is the blood type diet. On Episode #262 of The Tonic Talk Show/Podcast, health and wellness researcher David Nelson and I discussed this controversial approach to nutrition.
The blood type diet first gained popularity in 1996, introduced by Dr. Peter D’Adamo. His theory was bold: the four major blood types — A, B, AB, and O — evolved under different environmental conditions, meaning people with each type thrive on different diets.
- Type O, considered the oldest, supposedly benefits from a high-protein, meat-heavy diet.
- Type A does better with a plant-based approach.
- Type B is more mixed, tolerating dairy and meat.
- Type AB is said to need a more specialized, balanced intake.
Nelson, who personally knows Dr. D’Adamo, respects his work but emphasizes the importance of context. “In 1996, we didn’t know anything about the microbiome, so we looked elsewhere for patterns in health and disease. Blood type seemed like a promising lead.”
Nelson acknowledges that there are biological truths connected to blood types — for instance, the role of antigens on red blood cells and the potential immune reactions during pregnancy when blood types between mother and fetus conflict. But he cautioned against broad generalizations.
“The real issue,” Nelson says, “is that we now know there are over 40 different blood groups — not just four. So we can’t expect a one-size-fits-all approach to apply to everyone.”
While restrictive diets like this one can lead to weight loss, sustainability is often the bigger challenge. Nelson agrees, noting that many people are drawn to diet frameworks because they offer structure and a clear path — which can be helpful, especially for those feeling overwhelmed by weight loss.
Type O individuals are advised to eat meat, fish, vegetables, and fruit, avoiding grains and legumes. Type A should focus on vegetables, grains, and tofu. Type B has a broader selection, including meat and dairy, while type AB follows a more blended plan with some red meat but avoids foods like corn and buckwheat.
While this structure may give people a helpful starting point, Nelson cautions against rigidly sticking to it. “The diet can work, not necessarily because of blood type, but because it cuts out processed foods and introduces more whole, clean eating.” In that sense, he says, the benefits might come from general improvements in diet quality rather than any blood-type-specific magic.
The cost of maintaining a diet high in organic meats and specialty foods is a factor in its applicability. “It’s not cheap,” Nelson notes. “Eating organic is great, but if your plan relies heavily on animal protein, that can get expensive quickly.”
Beyond cost, many of these diets are paired with supplemental regimens; and while some supplements may help due to common nutrient deficiencies, they also turn diets into business models.
In addition to supplemental regimens, these diet regimes also include exercise recommendations. You can’t simply cherry-pick elements of these comprehensive plans. If someone only follows parts — say, eating for their blood type but skipping exercise or supplements — do they still benefit?
Nelson cautions, “Restrictive diets may be helpful for a time — for weight loss, or to reset habits — but they shouldn’t be lifelong. Eventually, you need to reintroduce variety to support your microbiome.”
So what’s the bottom line? According to Nelson, there’s no solid scientific evidence — no double-blind, placebo-controlled studies — proving the blood type diet works consistently. While it might help individuals in the short term, there’s no guarantee it’s effective or healthy for everyone.
That said, Nelson isn’t dismissing the diet entirely. “If it helps someone feel better, lose weight, and get healthier — great. But let’s not pretend it’s a universal solution.”
Instead, Nelson encourages people to learn from these diet models. “Take what works. Learn the wellness principles — like eating whole foods and reducing processed ones — and then broaden your diet over time to support long-term health.”
In a field where science still lags behind popular trends, one thing remains clear: the best diet is the one you can sustain, enjoy, and feel good on — no matter your blood type.
