The Germans did import large quantities of food through neutral powers, either directly or indirectly. However, the British were ultimately able to prevent this through a combination of military and diplomatic power.

Almost immediately after the start of the war, the Royal Navy imposed a blockade of Germany, capturing or forcing into neutral ports the vast majority of Germany's merchant marine (outside of the Baltic). This resulted in a major shortfall of significant imports in both food and strategic materials. The Germans sought to recoup these losses by importing them through neutrals - primarily the Netherlands and Denmark, but also Norway and Sweden. This could be done in two ways. Firstly, a cargo could be carried in a neutral (or even Allied) ship to a neutral port, where it was unloaded and then transshipped to Germany. The other option was for Germany to purchase supplies in a neutral power (above and beyond its peacetime imports), and then let the neutral power make up the ensuing shortfall through imports from the world market. This was done fairly extensively. As an example, in February 1914, imports to Sweden from the USA totalled $700,000; a year later, this figure had risen to $13,700,000. While some of this excess can be explained by increased domestic consumption and a need to replace imports from European powers that were no longer available, a significant proportion was re-exported to Germany. Over the course of 1915, imports of cotton to Norway were 97% higher than peacetime levels, oil 70% and metals 50%. For the second method, in 1916, 90% of Holland's agricultural produce was exported to Germany.

The British had several weapons they could use to block this trade. Its main military weapon was the 'Doctrine of Continuous Voyage'. This was a long-standing legal right which permitted a belligerent to seize contraband cargoes that were carried in neutral ships to neutral ports if it could be proven that the ultimate destination of the cargo was a belligerent power. Before the 1909 Declaration of London, this applied to all forms of contraband. Under the Declaration of London, Continuous Voyage applied only to absolute contraband (i.e. that with a solely military use) and not to conditional contraband (which had both civilian and military uses). Food was considered to be conditional contraband, so under the London Declaration the British could not legally stop it. However, the London Declaration had not been fully ratified by the start of the war. This meant that the British were legally, if not morally, in the right to stop food cargoes under continuous voyage. However, it only had a minor effect on German imports through neutral powers, as it was almost impossible to prove whether or not a cargo was ultimately destined for Germany.

More effective were legal and diplomatic tools. In December 1915, Britain's Parliament passed a Trading With the Enemy Act. Amongst other things, this forbade British merchants from trading with firms in neutral companies that were known to have connections with the enemy. A list of these firms was published in February 1916. Any business on this list could have ships in British ports impounded, and was forbidden from coaling in British ports too. This was a major threat, as Britain had a massive network of coaling stations. As a result, many of these neutral firms stopped trading with Germany, as the other alternative was the end of their company. Diplomatic efforts also bore fruit. One of the simpler methods was to purchase the majority of the produce of the neutrals that bordered Germany. In the case of Norway, the British began to purchase 85% of the country's fish catch from August 1916, essentially preventing it exporting any to Germany. Another option was the idea of the Navicert. This was, essentially, a passport for the goods a ship carried. A British official would inspect the ship's cargo before it departed. If it was deemed acceptable, then the ship would receive its navicert, a guarantee that the British blockade wouldn't stop the ship. This was a major competitive advantage for companies, providing an incentive to comply with the blockade, and also simplified the work of the blockade squadron.

A more coercive option was to threaten British exports, especially of coal, if the neutral power didn't reduce exports to Germany. In early 1917, British exports of coal to Norway were cut completely, to force Norway to stop exporting iron ore to Germany; this rapidly forced Norway to comply. The entry of the USA to the war only added to the effectiveness of this technique, with American embargoes of neutral powers doing significant economic damage. This could either force countries to negotiate with the Allies or remove their ability to export to Germany. Those countries that did negotiate found themselves forced into a system of rationing and purchasing agreements. In these systems, the Allies controlled how much the neutral powers were allowed to import and export, greatly reducing exports to Germany from the neutrals.