After pleading guilty, Arturo Eliseo Martinez-Barrera appeals his conviction and 151-month sentence for conspiracy to possess with intent to distribute at least 1,000 kilograms of marijuana, in violation of 21 U.S.C. § 841(a)(1), (b)(1)(A)(vii) and 18 U.S.C. § 2.
On appeal, Martinez-Barrera challenges the voluntariness of his guilty plea. The magistrate judge conducted the plea colloquy and issued a report (“R & R”) recommending that the district court accept Martinez-Barrera’s guilty plea to Count 1. Martinez-Barrera filed no objections, and the district court accepted his plea. On appeal, Martinez-Barrera argues that the magistrate judge did not advise him of the consequences of his guilty plea, in violation of Federal Rule of Criminal Procedure 11, and thus his guilty plea should be set aside.1
We lack jurisdiction to review the validity of Martinez-Barrera’s guilty plea because he did not file a written objection to the magistrate judge’s R & R. See Fed.R.Crim.P. 59(b)(2) (providing that the failure to file a written objection to the magistrate judge’s proposed findings and recommendations with regard to a disposi-tive matter “waives a party’s right to review”).2 Thus, Martinez-Barrera’s conviction is affirmed. See United States v. Rodriguez-Velasquez, 132 F.3d 698, 698 (11th Cir.1998) (explaining that we affirm the district court’s ruling if the defendant waived his right to appeal and no manifest injustice occurred).
Martinez-Barrera also argues that his sentence is substantively unreasonable under United States v. Booker, 543 U.S. 220, 125 S.Ct. 738, 160 L.Ed.2d 621 (2005). However, Martinez-Barrera’s plea agreement contained a sentence-appeal waiver, which stated that Martinez-Barrera “waive[d] the right to appeal [his] sentence or to challenge it collaterally on any ground” so long as the sentence: (1) was *535not above the court-determined advisory guidelines range; (2) did not exceed the statutory maximum sentence; and (3) did not violate the Eighth Amendment.
None of the circumstances under which Martinez-Barrera reserved his right to appeal his sentence has occurred. Martinez-Barrera’s 151-month sentence fell within the court-determined advisory guidelines range of 151 to 188 months imprisonment and did not exceed the statutory maximum of life imprisonment for his offense, see 21 U.S.C. § 841(b)(1)(A). On appeal, Martinez-Barrera does not argue that his sentence violated the Eighth Amendment. Furthermore, the language of the sentence-appeal waiver is broad enough to encompass a reasonableness challenge. See United States v. Grinard-Henry, 399 F.3d 1294, 1296 (11th Cir.2005) (explaining that broad language in an appeal waiver may include an appeal based on Booker). Therefore, if enforceable, Martinez-Barrera’s sentence-appeal waiver precludes review of his reasonableness claim.
Martinez-Barrera argues that his sentence-appeal waiver is invalid because the district court failed to adequately explain the appeal waiver during his plea colloquy.3 A sentence-appeal waiver must be knowing and voluntary and will be enforced if the government shows either that: (1) the district court specifically questioned the defendant about the waiver; or (2) the record makes clear that the defendant otherwise understood the full significance of the waiver. United States v. Bushert, 997 F.2d 1343, 1350-51 (11th Cir.1993).
Here, during the plea colloquy, the magistrate judge specifically discussed the sentence-appeal waiver and its exceptions with Martinez-Barrera. Martinez-Barrera stated under oath that he understood tile sentence-appeal waiver. We apply a strong presumption that Martinez-Barrera’s statement under oath that he understood the sentence-appeal waiver in his plea agreement was true, and Martinez-Barrera has failed to meet the heavy burden to show otherwise. See United States v. Medlock, 12 F.3d 185, 187 (11th Cir.1994); United States v. Rogers, 848 F.2d 166, 168 (11th Cir.1988).
Because Martinez-Barrera knowingly and voluntarily entered into his sentence-appeal waiver, the sentence-appeal waiver is enforceable. Thus, we do not address Martinez-Barrera’s reasonableness argument and dismiss his appeal of his sentence.
AFFIRMED IN PART; DISMISSED IN PART.