decreased $4.2 million, or 9.7%; and net sales of Cream of Wheat decreased $0.4 million, or 1.7%, in the first quarter of 2023, as compared to the first quarter of 2022. Base business net sales of all other brands in the aggregate decreased $0.7 million, or 0.8%, for the first quarter of 2023, as compared to the first quarter of 2022.
Gross profit was $114.2 million for the first quarter of 2023, or 22.3% of net sales. Excluding the negative impact of $0.7 million of acquisition/divestiture-related expenses and non-recurring expenses included in cost of goods sold during the first quarter of 2023, the Company’s gross profit would have been $114.9 million, or 22.4% of net sales. Gross profit was $101.3 million for the first quarter of 2022, or 19.0% of net sales. Excluding the negative impact of $2.1 million of acquisition/divestiture-related expenses and non-recurring expenses included in cost of goods sold during the first quarter of 2022, the Company’s gross profit would have been $103.4 million, or 19.4%.
During fiscal 2022, the Company’s gross profit was negatively impacted by higher than expected input cost inflation, including materially increased costs for raw materials and transportation. The Company expects input cost inflation will continue to have a significant industry-wide impact during the remainder of fiscal 2023. The Company has been attempting to mitigate the impact of inflation on its gross profit by locking in prices through short-term supply contracts and advance commodities purchase agreements and by implementing cost saving measures. The Company also announced several rounds of list price increases in 2021, 2022 and during the first quarter of 2023. However, the effective date of increases in the prices the Company charges its customers generally lag behind rising input costs. As such, the Company did not fully offset the incremental costs that it faced in fiscal 2022. However, during the fourth quarter of 2022, the Company began to more fully realize the benefits of previously announced list price increases. This trend continued during the first quarter of 2023, with the impact of previously announced list price increases the primary driver of a recovery in gross profit, which as described above, increased during the first quarter of 2023 as compared to the first quarter of 2022.
Selling, general and administrative expenses decreased $0.1 million, or 0.2%, to $46.7 million for the first quarter of 2023 from $46.8 million for the first quarter of 2022. The decrease was composed of decreases in warehousing expenses of $1.7 million, selling expenses of $1.1 million and consumer marketing expenses of $0.1 million, largely offset by increases in general and administrative expenses of $2.3 million and acquisition/divestiture-related and non-recurring expenses of $0.5 million. Expressed as a percentage of net sales, selling, general and administrative expenses increased by 0.3 percentage points to 9.1% for the first quarter of 2023, as compared to 8.8% for the first quarter of 2022.
Net interest expense increased $12.6 million, or 47.1%, to $39.4 million for the first quarter of 2023 from $26.8 million for the first quarter of 2022. The increase was primarily attributable to higher interest rates on the Company’s variable rate borrowings, as well as the accelerated amortization of deferred debt financing costs relating to the prepayments described below, partially offset by a reduction in average long-term debt outstanding. The reduction in average long-term debt outstanding in the first quarter of 2023 as compared to the first quarter of 2022 resulted primarily from the Company’s use of $50.0 million of the gross proceeds of the Back to Nature divestiture and an additional $71.0 million of cash on hand to make aggregate prepayments of $121.0 million principal amount of term loans during the first quarter of 2023, partially offset by an increase in average revolver borrowings outstanding of approximately $77.7 million.
The Company’s net income was $3.4 million, or $0.05 per diluted share, for the first quarter of 2023, compared to net income of $23.7 million, or $0.34 per diluted share, for the first quarter of 2022. Net income and diluted earnings per share for the first quarter of 2023 were negatively impacted by the net negative impact on income tax expense of $14.7 million, or $0.21 per share, resulting from the Back to Nature divestiture. The Company’s adjusted net income for the first quarter of 2023 was $19.1 million, or $0.27 per adjusted diluted share, compared to adjusted net income of $19.9 million, or $0.29 per adjusted diluted share, for the first quarter of 2022.
For the first quarter of 2023, adjusted EBITDA was $82.4 million, an increase of $9.4 million, or 12.9%, compared to $73.0 million for the first quarter of 2022. The increase in adjusted EBITDA was primarily attributable to the improvement in gross profit described above. Adjusted EBITDA as a percentage of net sales was 16.1% for the first quarter of 2023, compared to 13.7% for the first quarter of 2022.