Terry A. Zenker appeals from the district court’s order affirming the decision of the Secretary of Health and Human Services to deny his applications for disability insurance benefits and Supplemental Security Income (SSI) benefits under Titles II and XVI of the Social Security Act. The sole issue on appeal is whether there is substantial evidence in the record to support the finding of the Secretary that Zenker is not entitled to benefits under the Act. As we are convinced that substantial evidence does support this decision, we affirm.
I. BACKGROUND
Zenker filed his application for disability and SSI benefits on September 16, 1986, alleging disability as of June 1,1983, due to a learning impairment and a speech impediment. Zenker also suffers from chronic bronchitis, a seizure disorder, hypertension, alcoholism, and Klinefelter’s syndrome. The record indicates that Zenker, now 48 years old, is only 5'2" tall and weighs approximately 113 pounds.
It appears that Zenker attended school until age 17 or 18, having had to repeat the third and fourth grades once, and the fifth grade twice. He testified that he did not complete the eighth grade but the record is unclear as to whether Zenker spent eight actual years in school or if he entered eighth grade and failed to finish out that school year. Nevertheless, it is conceded by the Secretary that Zenker functions within the borderline mental range of ability-1
Zenker testified at the administrative hearing that in the past he worked as a cook in several restaurants but was unable to continue this work due to alcoholism and physical limitations brought on by hernias. He first received alcohol dependency treatment at a North Dakota State Hospital in 1982. Although Zenker can now be categorized as a recovering alcoholic, he has had at least two alcohol-related hospitalizations since that time. When hospitalized in July 1983, Zenker weighed only 87 pounds and suffered from malnutrition and tuberculosis. He also underwent hernia operations in 1982, 1983 and 1985.
In November 1982, Zenker began vocational training at Pride Industries, a rehabilitation center for developmentally disabled adults. He remained in Pride’s rehabilitation program until March 1984, at which time he was placed by Pride with the Bismarck Elks Lodge as a dishwasher. Still employed by the Lodge, Zenker works approximately twenty hours a week at *270$3.35 an hour, washing pots and pans, scrubbing floors, wrapping baked potatoes, baking garlic bread and placing seafood on ice.
An AU held that Zenker’s borderline mental functioning constitutes a severe impairment, but not severe enough to constitute an impairment listed in Appendix 1 to Subpart P, Part 404. He also found that Zenker’s speech impediment and episodic alcoholism imposed no significant limitations on his work-related activities. The AU determined that Zenker was able to perform unskilled, simple, repetitive work at all exertional levels. Based on the fact that Zenker was able to work at the Elks Lodge for approximately twenty hours a week, the AU held that Zenker could work an eight-hour day, five days a week. Thus, although Zenker had not engaged in substantial gainful activity since 1983, the AU felt that Zenker’s work activity at the Elks Lodge indicated that he could do so in the future.
II. DISCUSSION
Zenker argues on appeal that substantial evidence does not exist to support the AU’s finding that Zenker could function as a dishwasher on a full-time basis. We disagree.
If a claimant is not presently engaged in substantial gainful activity but is not precluded from doing so by physical or mental impairments, the Secretary will find no disability. 20 C.F.R. § 404.1571. To determine whether a claimant can engage in substantial gainful activity, the Secretary will examine the claimant’s earnings, the nature of his or her work, how well the claimant performs, and the amount of time spent working. Burkhalter v. Schweiker, 711 F.2d 841, 844 (8th Cir.1983). Present levels of work activity may show that a claimant is able to do more work than he or she is actually doing. 20 C.F.R. § 404.1571.
The AU found, in the present case, that Zenker’s ability to spend 20 hours a week at the Elks Lodge washing dishes and his satisfactory performance at this job indicated that Zenker could engage in substantial gainful activity. Our role on appeal is to determine whether that decision is supported by substantial evidence on the record as a whole. Clarke v. Bowen, 843 F.2d 271, 272 (8th Cir.1988). The substantiality of evidence must take into account whatever in the record detracts from its weight. Piercy v. Bowen, 835 F.2d 190, 191 (8th Cir.1987).
The record establishes that Zenker works three days a week for approximately six and one-half hours each day. Thus, he works approximately twenty hours a week. Zenker receives the minimum wage of $3.35 an hour. In 1983, Zenker earned $1,7433.00; in 1984, he earned $3,799.00; and in 1985 he earned $2,037.00. In the first four months of 1987, Zenker had earned only $595.00. As the AU notes, Zenker’s earnings have consistently averaged under $300.00 per month. See 20 C.F.R. § 404.1574(b)(2)(vi) (presumption that claimant has engaged in substantial gainful activity if earnings average more than $300 a month); and 20 C.F.R. § 404.1574(b)(3)(vi) (presumption that claimant has not engaged in substantial gainful activity if earnings averaged less than $190 a month). Thus, the AU correctly found that Zenker has not engaged in substantial gainful activity since 1983. The issue presented is whether Zenker’s current level of work activity indicates he could tolerate working enough hours as a dishwasher to average more than $300 a month.
Bernice Garen, Zenker’s supervisor at the Elks Lodge, reported that Zenker misses a lot of work due to illness, needs assistance with lifting 100-pound sacks of potatoes, and needs to be reminded not to smoke in the kitchen. Although she felt Zenker needs supervision, she felt he requires no more than any of the other Elks employees performing similar work. She noted that after a busy six-hour work shift, Zenker appears “very played out,” and for that reason, she does not believe he could work full time at his job.
Zenker’s wife testified that she also felt Zenker is unable to work full time at the Elks Lodge. She stated that after a busy *271work shift Zenker’s arms and legs are weak and his neck is very tense. He comes home with headaches and, on occasion, stomach cramps. She related that Zenker often returns home angry because his coworkers treat him like a child when his speech defect makes it difficult for them to understand him. According to Zenker’s wife, the emotional stress and the physical exertion of the job would prevent Zenker from performing on a full-time basis.
Bryan Wetch, the Assistant Executive Director at Pride Industries, explained why Zenker was placed in a part-time position:
Through training, Terry acquired the necessary skills to be a responsible hard worker. At the close of his training, Terry was placed part-time at the Bismarck Elks. His health being a primary reason for part-time placement versus full-time. Terry had excessive absences throughout his training — two hernia operations and other general poor health practices (poor nutrition, smoking, drinking) has resulted in limited stamina.
As a result, Wetch doubted if Zenker could perform full-time employment.
The medical evidence does not clearly support Wetch’s observation that Zenker’s stamina for full-time work is sufficiently limited to preclude full-time work. Zenker underwent three hernia operations. After each operation, he could do no lifting for up to two months. According to Dr. Steven K. Hamar, the surgeon who performed these operations, Zenker received a clean bill of health after July 1,1985, and had no lifting restrictions at that time. Zenker testified, however, that his operations have made it difficult for him to lift the 100-pound sacks of potatoes at work. His supervisor corroborated this testimony. It is not clear from the evidence, however, that a 100-pound, without help, lifting requirement is imposed by Zenker’s present job.
Zenker apparently has also had recurring bouts with alcohol abuse. In July 1983, Zenker was hospitalized at Jamestown State Hospital and underwent a month of therapy for his addiction. On admission, Zenker was malnourished, weighing only 87 pounds. Furthermore, he was tested and treated for tuberculosis. Zenker returned to Jamestown State Hospital in February 1984, after he resumed drinking. He was discharged two days later, as the hospital felt out-patient treatment was adequate.
At present, Zenker suffers from chronic bronchitis, a seizure disorder, hypertension and, probably, Klinefelter’s syndrome. Dr. Arthur E. Van Vranken, Zenker’s current treating physician, stated:
Mr. Terry Zenker is a classical Klinefel-ter’s syndrome with mild mental retardation, low set ears, slightly web neck, and hypogonadism, usually sterile, short small stature; all of these things would indicate a Klinefelter’s syndrome and can only be proven by genetic studies, which could be done at the Mayo Clinic at much expense, however there is no question in my mind, but what he fits this picture.
Dr. Van Vranken concluded that all of Zenker’s mental and physical problems led to his feeling socially inept and inadequate. This, in turn, created the danger of further drinking and seizures. He stated:
Physically he is well enough to perform his job as a dish washer, but I doubt if his physical and emotional status would allow for a full time 40 hour per week position of any more than just mild responsibilities. And as you know such positions are unavailable for the most part except through programs such as Pride Industries.
In a letter dated August 25, 1987, Dr Van Vranken reiterated an opinion that Zenker “is able to work at light work on a part-time basis only, with minimal responsibilities * * *.” The Appeals Council dismissed Dr. Van Vranken’s second statement as contradictory to his earlier opinion. It is the AU’s responsibility to evaluate the evidence adduced and to make credibility and substantive evaluations of conflicting information. Although we may not have arrived at the same conclusion, we are not in a position to find that the AU was wrong in this instance.
Zenker’s wife, employer, rehabilitation counselor and treating physician are all of the opinion that Zenker cannot perform his *272present job on a full-time basis. Evidence which supports the AU’s finding to the contrary is Zenker’s statement at the hearing that he would work more than 20 hours a week if that work were available at the Elks Lodge3 and Dr. Van Vranken’s first letter.
III. CONCLUSION
Because we feel the record does contain substantial evidence to support the AU’s decision that Zenker can perform substantial gainful activity, we affirm.
. In 1982, Zenker tested as having a full scale IQ of 63, a verbal IQ of 65, and a performance IQ of 66. However, in August of 1985, a similar test revealed a full scale IQ of 73, a verbal IQ of 70, and a performance IQ of 80. Zenker attributed the earlier test results to inadequate eye glasses.
. A consultative examination was conducted by Dr. R.L. Jennings on January 20, 1987. Dr. Jennings stated that Zenker was not disabled, but that he "is probably going to have a difficult time applying himself to any type of task that is going to require a great deal of physical activity because of his size; and his speech problem is going to make it impossible for him to participate in any form of job where mentality is required and communications are required.” Dr. Jennings does not indicate, however, if Zenker’s speech impediment, mental retardation and physical limitations would preclude him from working more than three days a week at the Elks Lodge.