Here is a detailed explanation of why a diet that eliminates refined sugar, all grains, and starchy vegetables is expected to achieve the outcomes especially when carbohydrate intake is consistently kept below 50g per day. By removing the three major sources of dense carbohydrates, you naturally force your daily intake to be very low.

1. Natural Reduction to Very Low Carbohydrate (VLC) Levels

Food Group Eliminated	Primary Nutritional Impact	Resulting Carb Level
Refined Sugar (Sodas, candies, desserts, etc.)	Eliminates all added and high-glycemic sugar.	Significant reduction.
All Grains (Bread, pasta, rice, oats, corn, wheat)	Eliminates the main source of complex starches.	Major drop in daily carbs.
Starchy Food (Potatoes, sweet potatoes, parsnips, yams)	Eliminates high-carb root vegetables.	Pushes the total to very low levels.
Remaining Sources	Only trace carbohydrates remain from non-starchy vegetables (e.g., leafy greens, broccoli, asparagus) and potentially small amounts from nuts/seeds.	Naturally leads to <50g/day.

Once total carbohydrate intake is consistently below 50 grams per day (for most people), the body enters a metabolic state called nutritional ketosis, which triggers the mechanisms detailed below.

2. Physiological Mechanisms for Lowering Blood Pressure

The reduction in carbohydrates below 50g/day addresses the root causes of hypertension (high blood pressure) through multiple, reinforcing pathways:

A. Improved Insulin Sensitivity and Sodium Excretion (The “Water/Salt” Mechanism)

• Insulin and Salt Retention: High-carbohydrate diets lead to high insulin levels (hyperinsulinemia) in many individuals. High insulin signals the kidneys to re-absorb sodium (salt) instead of excreting it. Water follows salt, leading to increased fluid volume and constriction of blood vessels—a primary cause of high blood pressure.
• VLC Effect: By drastically reducing carbohydrate intake, circulating insulin levels fall significantly. This drop signals the kidneys to excrete excess sodium and water. This initial effect often leads to a rapid drop in blood pressure and body weight (“water weight”) within the first few weeks, which immediately lessens the pressure on the blood vessel walls.

B. Reduced Systemic Inflammation

Chronic, low-grade inflammation is a major driver of blood vessel damage, arterial stiffening, and hypertension.

• VLC/Ketone Effect:
  • Reduced Glucose Spikes: Eliminating refined carbs and starches removes the primary cause of rapid blood sugar spikes, which are pro-inflammatory.
  • Ketone Bodies as Anti-inflammatories: When the body is in ketosis, it produces ketone bodies, particularly -Hydroxybutyrate (BHB). Research shows that BHB acts as a signaling molecule that can directly suppress the NLRP3 inflammasome, a major cellular complex that drives inflammation in metabolic diseases. By calming this inflammatory pathway, a VLC diet helps reduce the overall systemic inflammation that contributes to vessel stiffness.

3. Mechanism for Gut Barrier Function Repair

The high-sugar/refined-carb diet is linked to intestinal permeability (often called “leaky gut”), where the tight junctions between intestinal cells become compromised.

• VLC Effect on Tight Junctions: Research suggests the ketogenic state may help restore the integrity of the gut lining.
  • Butyrate Production: While high-fibre diets are typically associated with Short-Chain Fatty Acids (SCFAs) like butyrate, the shift in the gut microbiome caused by a VLC diet can also influence SCFA production. Butyrate is the primary fuel source for the cells lining the colon and is crucial for repairing and maintaining the “tight junctions” (proteins like ZO-1 and occludin) that form the gut barrier.
  • Reduced Pathogenic Overgrowth: Restricting sugars and starches starves the specific types of gut bacteria (often those associated with “Western diets”) that can contribute to gut-lining damage and inflammation.

4. The Role of High-Collagen Foods (Salmon and Mackerel)

Adding high-collagen or fatty fish sources, like salmon and mackerel, is a strategic enhancement that complements the VLC strategy:

• Omega-3 Fatty Acids (EPA and DHA): Salmon and Mackerel are rich in long-chain Omega-3 fats.
  • Anti-Hypertensive: Omega-3s promote the production of compounds that cause vasodilation (relaxation and widening of blood vessels), directly contributing to lower blood pressure. They also help reduce the buildup of plaque in arteries.
  • Enhanced Anti-Inflammation: Omega-3s are powerful anti-inflammatory agents, adding to the anti-inflammatory effect of the ketogenic state.
• Collagen/Amino Acids:
  • Tissue Repair: Collagen is the main structural protein in connective tissues, including the walls of the arteries and the gut lining. Providing the building blocks (amino acids like Glycine and Proline) from foods rich in collagen supports the body’s natural processes for repairing and maintaining the elasticity of blood vessels and the integrity of the gut barrier.

This approach has been used for years. For example, one study found that 47% of participants on a low-carbohydrate diet were able to have their blood pressure medication decreased or discontinued after a short period, compared to 21% in a control group. This shows effectiveness but can’t be extrapolated globally. The combined effect of sustained weight loss, reduced fluid volume, improved insulin sensitivity, and reduced systemic inflammation can lead to a significant and sustained drop in blood pressure. If the patient’s blood pressure drops consistently into a healthy range (below 130/80 mmHg), the prescribing physician may deem the medication unnecessary or reduce the dosage. Consult with your doctor before taking this diet.

There is a shorter version of this explanation here.